JP2004056839A - Control system for permanent magnet type motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a permanent magnet type synchronous motor which can suppress cogging torque. <P>SOLUTION: A control system for the permanent magnet type synchronous motor is composed of a rotor equipped with a permanent magnet, and a stator where a coil is wound on a salient pole. Further, the system is equipped with an encoder 8 which detects the rotational angle position θ of the rotor, a torque map 1 which decides a d-axis current basic command value idt* and a q-axis current command value iq* from rotational angle velocity ωθand a torque command value τ*, a corrective current map 14 which decides the current correction ida of an axis (d) from the rotational angle position θ, a condition judger 17 which decides a d-axis current command value id* from the d-axis current basic command value idt* and the corrective current value ida*, and an adder 13. It controls a polyphase AC current flowing to a coil. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
[Industrial applications]
The present invention relates to a control system of a permanent magnet type synchronous motor that has a permanent magnet in a rotor and is driven by passing a multi-phase AC current through a stator, and more particularly to a control system that suppresses torque fluctuation.
[0002]
[Prior art]
In motors having a permanent magnet on the rotor and salient poles on the stator, torque fluctuations occur because the force at which the permanent magnet attracts the stator salient poles changes depending on the rotational angle position of the rotor. That is, it is known that cogging torque is generated. Such a cogging torque is, for example, a motor mounted on a vehicle as a driving source for traveling, which causes unpleasant vibration when the vehicle is traveling at a low speed immediately after starting or immediately before stopping or when the vehicle is traveling by inertia. May be communicated to others.
[0003]
As a method of reducing such cogging torque, a method as disclosed in Japanese Patent Application Laid-Open No. 2001-103783 is known. This is because when the driving speed of the motor and the generated torque are relatively low, the current of the d-axis component, which is the field weakening current, flows by a predetermined value, and the magnetic flux of the permanent magnet is weakened to suppress the torque fluctuation. Is to try.
[0004]
[Problems to be solved by the invention]
However, such a conventional method does not consider fluctuations in the suction force due to the angle of the rotor, and thus has a limit on the cogging torque that can be reduced. This is because the ratio of the magnetic flux weakened changes depending on the rotational angle position of the magnet even if a certain amount of the field weakening current flows.
[0005]
Therefore, an object of the present invention is to provide a control system of a permanent magnet type synchronous motor that can suppress cogging torque by changing a field weakening current value according to a rotational angle position.
[0006]
[Means for solving the problem]
According to the present invention, a rotation angle position of the rotor is detected by a permanent magnet type synchronous motor control system including a rotor having a permanent magnet and a stator having coils wound around a plurality of salient poles. Rotation angle position detecting means. Further, current command value determining means for determining a basic command value of the d-axis current and a command value of the q-axis current based on the rotational angular velocity and the target torque of the electric motor, and a d-axis current based on the rotational angle position. Correction current value determining means for determining a correction value; d-axis current command value determining means for determining a d-axis current command value based on the d-axis current basic command value and the d-axis correction current value; Current control means for controlling a polyphase alternating current flowing through the coil based on the command value and the q-axis current command value.
[0007]
[Action and effect]
Current command value determining means for determining a basic command value of the d-axis current and a command value of the q-axis current based on the rotational angular speed and the target torque of the motor; and a correction value of the d-axis current based on the rotational angle position. And a d-axis current command value determining means for determining the d-axis current command value based on the d-axis current basic command value and the d-axis correction current value. And a current control means for controlling a polyphase AC current flowing through the coil based on the d-axis current command value and the q-axis current command value.
[0008]
As described above, by correcting the d-axis current in accordance with the rotational angle position, the cogging torque can be effectively suppressed.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a control block diagram of a control system for a permanent magnet type synchronous motor used in the first embodiment. Here, the current value of the motor 7 is controlled according to the torque command value τ ^* . The motor 7 is provided with an encoder 8 for detecting the rotation angle position of the rotor, and a coil is wound around the salient pole of the stator of the motor 7 by concentrated winding.
[0010]
The control system includes an angle calculator 15 and a speed calculator 16. The rotation angle position θ is obtained by passing the output from the encoder 8 through the angle calculation unit 15, and the rotation angular speed ωθ is obtained by passing the output through the speed calculation unit 16. The rotational angular velocity ωθ and the torque command value τ ^* are input to a torque map 1 provided in the control system, and the optimal dq-axis current components are obtained, and the respective q-axis current command values iq ^* and d-axis power basic command values idt are obtained. Output as ^* .
[0011]
With respect to the q-axis current component, the q-axis current iq actually flowing to the motor 7 is subtracted from the q-axis current command value iq ^* in the adjusting unit 2 to obtain a difference Δiq. The difference Δiq is input to a PI controller 3-1 provided in the control system, where the difference Δiq is converted into a q-axis voltage command value Vq ^* acting in a direction to reduce the difference Δiq.
[0012]
Here, the measured value iq of the q-axis current is detected as follows.
[0013]
The control system includes an A / D converter 10 and a dq converter 11. Further, current sensors 9-1 and 9-2 for measuring a current sent to the motor 7 are provided, and a current value actually flowing to the motor 7 is detected. After the output is digitally converted by the A / D converter 10, it is input to the dq converter 11 and converted from three-phase values of u, v, and w into two-phase values of q and d. The q-axis current obtained at this time is defined as an actually measured value iq.
[0014]
On the other hand, as for the d-axis current component, the d-axis current basic command value idt ^* output from the torque map 1 is input to the adding unit 13. Further, the correction current value ida ^* obtained by the current correction map 14 based on the rotation angle position θ is also input to the addition unit 13. However, a condition determining unit 17 for performing control as described below is provided, and the correction current ida ^* is input from the correction current map 14 to the adding unit 13 only when the condition determining unit 17 determines that correction is necessary.
[0015]
The adder 13 adds the correction current value ida ^* and the d-axis current basic command value idt ^*, and sets the sum as a d-axis current command value id ^* . Next, similarly to the processing of the q current component, the actual measurement value id of the d-axis current is subtracted from the d-axis current command value id ^* by the adjustment unit 12. The actually measured value id of the d-axis current is a d-axis current value that is converted simultaneously with the q-axis current value by the dq converter 11 described above. The difference Δid output as a result is input to a PI controller 3-2 provided in the control system, and converted into a d-axis voltage command value Vd ^* that reduces the difference Δid according to the difference Δid.
[0016]
The thus-calculated dq-axis voltage command values Vd ^* and Vq ^* are input to the dq inverse converter 4 provided in the control system, and the two-phase voltage values of q and d are converted into three-phase voltages of u, v and w. Convert to voltage value. Further, a PWM signal generator 5 and a drive circuit 6 are provided, and the voltage is applied to the motor 7 after the pulse width is modulated. Here, the above-described current sensors 9-1 and 9-2 measure a current value supplied from the drive circuit 6 to the motor 7.
[0017]
Next, the operation of the correction current map 14 and its output will be described.
[0018]
The rotor of the motor 7 is provided with a permanent magnet, so that a torque corresponding to the rotation angle of the rotor, that is, a cogging torque is generated even when no drive current is flowing. If the target torque of the motor 7 is zero, that is, if the motor 7 is driven by another driving device and is running idle, there is a possibility that vibration or noise due to the cogging torque may occur. This is a problem particularly when the motor 7 is mounted on a vehicle as a driving source of the vehicle.
[0019]
It is known that the cogging torque is generated during one rotation of the motor 7 for a period represented by the least common multiple of the number of poles of the rotor and the number of salient poles of the stator. A method of increasing the least common multiple has been generally adopted.
[0020]
On the other hand, in a high-output, high-efficiency synchronous motor represented by a so-called IPM, which is characterized by a shape in which a permanent magnet is embedded in a stator, a coil is fixed in order to reduce the size and cost. Concentrated winding IPM, which is concentratedly wound on a child salient pole, has been widely used.
[0021]
However, such a concentrated winding type motor does not have as many degrees of freedom as salient poles than the distributed winding type. Therefore, measures such as changing the magnet peripheral shape and the salient pole shape to reduce cogging torque are taken. Is normal. In this case, it is necessary to consider the effects on performance and efficiency, and at the same time, it is inevitable that the cost will increase due to the processing steps and processing accuracy.
[0022]
Therefore, as another method of suppressing cogging torque, among the dq-axis current components, the d-axis current component is a current component having the same direction as the magnetic flux generated by the magnet. In other words, a method of weakening the magnetic flux of the magnet by flowing in the direction of the weakening magnetic field is known. However, the degree to which the weak magnetic field current acts on the permanent magnet, that is, the degree to which the influence of the magnetic flux of the permanent magnet is weakened by the d-axis current, changes depending on the rotational angle position θ of the rotor of the motor 7. Therefore, it has been difficult to efficiently suppress the cogging torque even when a certain amount of the d-axis current flows.
[0023]
Therefore, in the present embodiment, the rotation angle position θ of the rotor obtained by passing the output of the encoder 8 through the rotation position calculation unit 15 is input to the correction current map 14, and the cogging torque is suppressed most at the rotation angle position θ. A correction current value ida ^* that can be performed is determined. The waveform of the correction current value ida ^* varies depending on various conditions such as the shape of the motor 7 and the like, for example, as shown in FIG.
[0024]
The correction current value ida ^* thus determined is added to the d-axis current basic command value idt by the condition judging unit 17 in the adding unit 13 only when the torque command value τ ^* of the motor 7 is smaller than a predetermined value, for example, zero. Add to ^* . Here, if the torque command value τ ^* is not equal to or more than the predetermined value, the addition is not performed, and the d-axis current basic command value idt ^* is set as the d-axis current command value id ^* . Here, the predetermined value is a limit value in a torque region where vibration and noise due to cogging torque do not feel uncomfortable for the driver. That is, the d-axis current is corrected only when the user feels discomfort due to the cogging torque, and the cogging torque is suppressed.
[0025]
Next, a method of determining the d-axis current command value id ^* will be described with reference to the flowchart of FIG.
[0026]
First, in step S1, the condition determination unit 17 determines whether the d-axis current basic command value idt ^* output from the torque map 1 is smaller than a predetermined value, here, is zero. If it is not zero, it is considered that the generation of the torque of the motor 7 is required, so the process proceeds to step S5, and the d-axis current basic command value idt ^* is used as the d-axis current command value id ^* .
[0027]
On the other hand, if the d-axis current basic command value idt ^* is not zero, the process proceeds to step S2 to determine whether the q-axis current command value iq ^* is zero. Also at this time, if the q-axis current command value iq ^* is not zero, it is determined that the generation of torque is requested, and the process proceeds to step S5.
[0028]
If it is determined in steps S1 and S2 that iq ^* and idt ^* are zero, that is, the torque command value τ ^* is zero, it is determined that unpleasant vibration or noise may occur due to cogging torque, and the process proceeds to step S3. move on. In step S3, the output from the correction current map 14 and the correction current value ida ^* are read into the adder 13. Next, in step S4, the d-axis current command value id ^* is obtained by adding the d-axis current basic command value idt ^* and the correction current value ida ^* by the adding unit 13.
[0029]
Thereafter, the current value flowing to the motor 7 is controlled from the d and q axis current command values id ^* and iq ^* as described above. By performing such control, the cogging torque of the motor 7 is effectively suppressed.
[0030]
Next, effects produced by the present embodiment will be described. FIG. 4 illustrates the effect.
[0031]
A correction current map 14 for determining a correction current value ida ^* based on the rotational angle position θ, and a condition determination for determining a d-axis current command value id ^* based on the d-axis current basic command value idt ^* and the correction current value ida ^*. And a current control means for controlling the polyphase alternating current flowing through the coil based on the d-axis current command value id ^* and the q-axis current command value iq ^* .
[0032]
As described above, by correcting the d-axis current id according to the rotation angle position θ of the motor 7, a weak magnetic field corresponding to the rotation transfer angle position θ can be generated, and the correction is performed as shown in FIG. The cogging torque can be reduced more efficiently than in the case where there is no cogging torque.
[0033]
Further, as current control means, current sensors 9-1 and 9-2 for detecting the value of the polyphase alternating current flowing through the coil, and the detected values of the polyphase alternating current using the rotational angle position θ are used as d-axis currents id and q. There is provided a dq converter 11 for converting to a shaft current iq. Further, voltages for calculating d-axis voltage command values Vd ^* and Vq ^* for reducing deviations Δid and Δiq between d and q-axis currents id and iq and d and q-axis current basic command values id ^* and iq ^* , respectively. Command value calculation means, here, PI controllers 3-1 and 3-2 are provided. Further, a dq inverse converter 4 for converting the d-axis voltage command value Vd ^* and the q-axis voltage command value Vq ^* into a polyphase AC voltage command value using the rotation angle position θ is provided.
[0034]
By configuring the current control means as described above, the difference between the actually measured values id and iq of the d and q axis current values and the command values id ^* and iq ^* corresponding to the rotation angle position θ is reduced. Set the voltage command values Vd ^* and Vq ^* . Thereby, the influence of the cogging torque can be reduced according to the rotation angle position θ.
[0035]
In addition, in the adder 13 as the d-axis current basic command value determining means, an addition value of the d-axis current basic command value idt ^* and the correction current value ida ^* is set as the d-axis current command value id ^* . Accordingly, the correction current value ida ^* can be added so as to reduce the cogging torque estimated according to the rotation angle position θ, so that vibration, noise, and the like due to the cogging torque can be suppressed.
[0036]
Further, the condition judging unit 17 as the d-axis current basic command value determining means converts the d-axis current basic command value idt ^* to the d-axis current when the magnitude of the torque command value τ ^* of the motor 7 is larger than a predetermined value. Determined as the command value id ^* . On the other hand, when the magnitude of the torque command value τ ^* is not larger than the predetermined magnitude, the correction using the correction current value ida ^* is performed. Accordingly, when vibration, noise, and the like due to the cogging torque become remarkable, the d-axis correction current ida ^* is supplied, and the cogging torque can be suppressed. Further, in the high torque region where vibration and noise due to cogging torque are less likely to cause discomfort, the d-axis current value id is not corrected, so that wasteful power consumption can be prevented.
[0037]
In particular, by setting the predetermined magnitude to zero, it is possible to suppress the occurrence of unpleasant vibration particularly when the motor 7 is not operating, that is, when the vehicle is running by inertia.
[0038]
The present embodiment is also effective for a motor in which a coil is wound by concentrated winding with a small degree of freedom of salient poles. At this time, since the cogging torque can be suppressed with a small correction current value ida ^* , power consumption can be reduced.
[0039]
In the present embodiment, the rotational angular velocity ωθ is obtained by inputting the rotational angular position θ to the velocity calculation unit 16, but is not limited to this. The torque command value τ ^* to be input to the torque map 1 can be calculated by another control system (not shown) by depressing an accelerator or the like.
[0040]
Next, a second embodiment will be described. The control block diagram here is the same as FIG. 1 shown in the first embodiment. Only the output from the correction current map 14 and the action of the correction current value ida ^* are different from those of the first embodiment. FIG. 5 shows a control flow for obtaining the d-axis current command value id ^* .
[0041]
FIG. 5 is obtained by inserting step S6 between steps S2 and S3 in the flowchart shown in FIG. In step S6, the absolute value of the rotational speed ωθ of the motor 7 determines whether less than a predetermined value omega _0.
[0042]
Thus, whether to add the correction current value ida ^* for suppressing the cogging torque is determined based on the value of the torque command value τ ^* and the rotational angular velocity ωθ of the motor 7. Thus, even if the torque command value τ ^* is zero, the correction current value ida ^* for suppressing the cogging torque is not added if the rotational angular speed ωθ of the motor is equal to or more than the predetermined value.
[0043]
When the motor 7 is used as a driving source for running the vehicle, cogging torque poses a problem only in a relatively low frequency range where a driver or the like feels vibration or the like due to cogging torque. In the present embodiment, the cogging torque is reduced only in that region, and normal control is performed in a high-frequency region where no human can feel.
[0044]
Thus, the condition determining unit 17 as a d-axis current basic command value determining means in the present embodiment, when the rotational angular velocity ωθ of the motor 7 is larger than the predetermined value omega _0, the d-axis and d-axis current basic command value idt ^* a current command value id ^*, when not larger than the predetermined value omega _0, performing the correction using the correction current ida ^*. As a result, the cogging torque is suppressed only when the vehicle that is greatly affected by the vibration and noise due to the cogging torque is in the low-speed region, so that the cogging torque is effectively suppressed and the power consumption in the high rotation region is simultaneously achieved. Can be reduced.
[0045]
Next, a third embodiment will be described. FIG. 6 shows a control flow for obtaining the d-axis current command value id ^* , and the other parts are the same as in the first embodiment.
[0046]
FIG. 6 is a flowchart (FIG. 5) according to the second embodiment, in which step S7 is inserted between step S6 and step S3. In step S7, it is determined whether the rotational angular velocity ωθ is not zero. When the rotational angular velocity ωθ is zero, the d-axis current basic command value idt ^* is set as the final d-axis current basic command value id ^*, and the correction current ida for suppressing the cogging torque only when the rotational angular velocity ωθ is not zero. Add ^* .
[0047]
In order to suppress the cogging torque as described above, the correction current ida ^* is added when the torque command value τ ^* is zero and the absolute value of the rotation speed ωθ of the motor 7 is larger than _{zero and} smaller than ω0.
[0048]
As shown in FIG. 2, the d-axis current value id for suppressing cogging torque is a relatively large current value depending on the angular position θ at which the motor 7 is stopped. On the other hand, when the rotation speed ωθ = 0, the correction current value ida ^* is not added.
[0049]
As described above, when the rotational angular velocity ωθ is zero, the correction current value ida ^* for suppressing the cogging torque is not added, so that a large current is prevented from continuously flowing through the coil when the vehicle is stopped. be able to. For example, when the motor 7 is stopped for a long time, unnecessary large current can be prevented from continuously flowing through the coil. As a result, the power consumption of the motor 7 can be reduced, and the temperature rise of the coil can be suppressed.
[0050]
Next, a fourth embodiment will be described. FIG. 7 shows a control block of the control device used here.
[0051]
Here, instead of the condition determining unit 17 that determines whether to perform correction in the first to third embodiments and the adding unit 13 that adds the d-axis current basic command value idt ^* and the corrected current value ida ^*. A maximum value selector 18 is provided. In the maximum value selection unit 18, the correction current ida ^* and d-axis current basic command value idt ^* selectively rather than adding, by comparing the sequential correction current ida ^* and d-axis current basic command value idt ^* , The one with the larger absolute value is defined as the d-axis current command value id ^* .
[0052]
Here, FIG. 8 shows a control flow in the maximum value selection unit 18 for determining the d-axis current command value id ^* .
[0053]
In step S11, the d-axis current basic command value idt ^* and the correction current value ida ^* are read. In step S12, the absolute values of the d-axis current basic command value idt ^* and the corrected current value ida ^* are compared. If the absolute value of the d-axis current basic command value idt ^* is larger than the absolute value of the correction current value ida ^* , the process proceeds to step S13, and the d-axis current basic command value idt ^* is adopted as the d-axis current command value id ^* .
[0054]
On the other hand, if the absolute value of the d-axis current basic command value idt ^* is equal to or smaller than the absolute value of the correction current value ida ^* in step S12, the process proceeds to step S14, where the correction current value ida ^{* is} set as the d-axis current command value id ^{* .} Is adopted.
[0055]
Thus, for example, when the torque command value τ ^* is zero and the d-axis current basic command value idt ^* output from the torque map 1 is also zero, the correction current value ida ^* is selected and output. On the other hand, if the torque command value τ ^* has a certain value other than zero from that state, the d-axis current basic command value idt ^* output from the torque map 1 and the d-axis correction current map 14 are output. Compare the correction current value ida ^* and select the one with the larger absolute value.
[0056]
Specifically, the peak of the current waveform of the d-axis correction current value ida ^* as shown in FIG. 9, where the d-axis current has a negative value, and the peak formed nearer to zero has a negative value. , D-axis current basic command value idt ^* . This is because the d-axis current basic command value idt ^* is constant with respect to the rotation angle position θ of the motor 7.
[0057]
As described above, in the maximum selection unit 18 as the d-axis current basic command value determining means, the larger absolute value of the d-axis current basic command value idt ^* and the correction current value ida ^* is determined by the d-axis current command value id ^*. To be determined. As a result, when torque is generated from a state where the torque command value τ ^* is zero, the current continuously changes, so that uncomfortable vibration is not given to the driver, and the angle depends on the angle in the torque generating state. Torque fluctuation, that is, torque ripple, can be reduced.
[0058]
Next, a fifth embodiment will be described. FIG. 10 shows a control flow showing a method of determining the d-axis current command value id ^* in the maximum value selection unit 18 used here, and the other parts are the same as in the fourth embodiment.
[0059]
In FIG. 10, step S10 is inserted before step S11 in the control flow (FIG. 8) used in the fourth embodiment. In step S10, the absolute value of the rotation angular velocity ωθ to determine whether greater than a predetermined value omega _0. If the absolute value of the rotation angular velocity ωθ is smaller than a predetermined value omega ₀ the process proceeds to step S11, and as in the fourth embodiment below.
[0060]
On the other hand, in step S10, when the absolute value of the rotational speed ωθ is ₀ or greater than a predetermined value ω, the process proceeds to step S13, employs a d-axis current basic command value idt ^* as the d-axis current command value id ^*.
[0061]
Thereby, in addition to the effects obtained in the fourth embodiment, the effects obtained in the second embodiment can be obtained. That is, in the high rotation region where the driver does not feel, the increase in the current consumption is suppressed without suppressing the cogging torque, and the cogging torque can be suppressed so as not to generate vibration or the like in the low rotation region.
[0062]
Next, a sixth embodiment will be described. FIG. 11 shows a control flow in the maximum value selection unit 18 used here, and the other parts are the same as in the fourth embodiment.
[0063]
In FIG. 10, step S15 is inserted between step S10 and step S11 in the control flow (FIG. 10) used in the fifth embodiment. In step S15, it is determined whether the rotation speed ωθ is zero. If the rotation speed ωθ is not zero, the process proceeds to step S11, and the same control as in FIG. 10 is performed. If the rotation speed ωθ is zero, the process proceeds to step S13, and the d-axis current basic command value idt ^* is adopted as the d-axis current command value id ^* .
[0064]
By doing so, it is possible to obtain the effect obtained in the third embodiment in addition to the effect obtained in the fifth embodiment. That is, when the motor 7 is stopped, a large current is prevented from continuously flowing through the coil, thereby increasing power consumption and suppressing heat generation of the coil.
[0065]
Next, a seventh embodiment will be described. Here, in any one of the first to sixth embodiments, the correction current map 14 shown in FIG. 12 is used.
[0066]
In FIG. 12, the correction current value ida ^* based on the rotation angle position θ uses a waveform that can be calculated by a simple trigonometric function. FIG. 13 shows the effect of reducing the cogging torque when such a correction current is used.
[0067]
When the map is used, it is necessary to reduce the increment of the rotation angle position θ in order to improve the control accuracy, which has been a factor for increasing the memory usage, for example. This can be calculated by a relatively simple mathematical expression. Here, as shown in FIG. 12, by adopting a sinusoidal correction current value ida ^* for the rotation angle position θ, the memory consumption is reduced. At the same time, the correction current value ida ^* can be determined at high speed.
[0068]
It is needless to say that the present invention is not limited to the above-described embodiment, and various changes can be made within the scope of the technical idea described in the claims.
[Brief description of the drawings]
FIG. 1 is a control block diagram of a control device according to a first embodiment.
FIG. 2 is a correction current map according to the first embodiment.
FIG. 3 is a flowchart of control for determining a basic d-axis current command value according to the first embodiment.
FIG. 4 is a diagram illustrating an effect of the first embodiment.
FIG. 5 is a flowchart of control for determining a d-axis current basic command value according to the second embodiment.
FIG. 6 is a flowchart of control for determining a d-axis current basic command value according to the third embodiment.
FIG. 7 is a control block diagram of a control device according to a fourth embodiment.
FIG. 8 is a flowchart of control for determining a basic d-axis current command value according to the fourth embodiment.
FIG. 9 is a diagram illustrating a d-axis current basic command value with respect to a rotational position obtained according to a fourth embodiment.
FIG. 10 is a flowchart of control for determining a d-axis current basic command value according to the fifth embodiment.
FIG. 11 is a flowchart of control for determining a d-axis current basic command value according to a sixth embodiment.
FIG. 12 is a correction current map according to a seventh embodiment.
FIG. 13 is a diagram illustrating effects of the seventh embodiment.
[Explanation of symbols]
1 Torque map (current command value determination means)
3 PI controller (voltage command value calculation means)
4 dq inverse converter (inverter)
8 Encoder (rotation angle position detection means)
9 Current sensor (current detection means)
11 dq converter (conversion means)
13 adder (d-axis current command value determining means)
14 Correction current map (correction current value determining means)
17 Condition judgment unit (d-axis current command value determination means)
18 Highest value selection section (d-axis current command value determination means)

Claims (9)

In a control system of a permanent magnet type synchronous motor including a rotor having a permanent magnet and a stator having coils wound around a plurality of salient poles,
Rotation angle position detection means for detecting the rotation angle position of the rotor,
Current command value determining means for determining a basic command value of the d-axis current and a command value of the q-axis current based on the rotational angular velocity of the electric motor and the target torque;
Correction current value determination means for determining a correction value of the d-axis current based on the rotation angle position;
D-axis current command value determining means for determining a d-axis current command value based on the d-axis current basic command value and the d-axis correction current value,
A control system for a permanent magnet synchronous motor, comprising: current control means for controlling a polyphase AC current flowing through the coil based on the d-axis current command value and the q-axis current command value. The current control means,
Current detection means for detecting a polyphase alternating current value flowing through the coil,
Conversion means for converting the detected value of the polyphase AC current into a d-axis current and a q-axis current based on the rotation angle position;
A d-axis voltage command value for reducing a deviation between the d-axis current obtained by the conversion and the d-axis current command value is calculated, and a deviation between the q-axis current obtained by the conversion and the q-axis current command value is calculated. Voltage command value calculation means for calculating a q-axis voltage command value for reducing
The control of a permanent magnet type synchronous motor according to claim 1, further comprising: an inverse conversion unit configured to convert the d-axis voltage command value and the q-axis voltage command value into a polyphase AC voltage command value using the rotation angle position. system. In the d-axis current command value determining means,
The control system for a permanent magnet synchronous motor according to claim 1 or 2, wherein an added value of the d-axis current basic command value and the d-axis correction current value is determined as the d-axis current command value. In the d-axis current command value determining means,
3. The control system for a permanent magnet synchronous motor according to claim 1, wherein a larger absolute value of the d-axis current basic command value and the d-axis correction current value is determined as the d-axis current command value. 4. In the d-axis current command value determining means,
When the magnitude of the target torque of the motor is larger than a predetermined magnitude, the d-axis current basic command value is determined as the d-axis current command value,
The control system for a permanent magnet type synchronous motor according to claim 3 or 4, wherein the correction using the d-axis correction current value is performed when the magnitude of the target torque of the motor is not larger than a predetermined magnitude. The control system for a permanent magnet type synchronous motor according to claim 5, wherein the predetermined size is set to zero. In the d-axis current command value determining means,
When the magnitude of the rotational angular velocity of the motor is larger than a predetermined magnitude, the d-axis current basic command value is determined as the d-axis current command value,
The control system for a permanent magnet type synchronous motor according to claim 3 or 4, wherein the correction using the d-axis correction current value is performed when the rotation angular velocity of the motor is not greater than a predetermined value. In the d-axis current command value determining means,
5. The control system for a permanent magnet synchronous motor according to claim 3, wherein the d-axis current basic command value is determined as the d-axis current command value when the magnitude of the rotational angular velocity of the motor is substantially zero. In the correction current value determining means,
The control system for a permanent magnet type synchronous motor according to any one of claims 1 to 8, wherein the control system has a sinusoidal d-axis correction current value with respect to the rotation angle position.

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