JP4764124B2 - Permanent magnet type synchronous motor control apparatus and method - Google Patents

Description

  The present invention relates to a control device for a permanent magnet type synchronous motor, and more particularly, to a control device for a permanent magnet type synchronous motor that has a simple configuration and performs high-efficiency control with a minimum current. is there.

  The torque τ of the permanent magnet type synchronous motor is generally expressed by the following equation (1).

  Here, Λd is an induced voltage coefficient, and id and iq are armature currents of d-axis and q-axis, respectively. Ld and Lq are the d-axis and q-axis inductances, respectively, and n is the number of pole pairs. The d axis is an axis provided in the field direction of the motor rotor, and the q axis is an axis whose phase is advanced 90 degrees from the d axis.

  The first term of equation (1) represents the torque (magnet torque) generated by the q-axis current flowing in a direction perpendicular to the field direction by the magnet. Further, the second term of the same expression represents the torque (reluctance torque) generated when the reluctance is different between the d-axis direction and the q-axis direction. In the surface magnet type motor (SPM) where Ld = Lq, the second term can be ignored. Even in the case of an internal magnet type motor (IPM), if the difference between Ld and Lq is small, the second term is often ignored.

  For this reason, when controlling a permanent magnet type synchronous motor, if it can be controlled to Id = 0, torque can be generated with the least current, and the efficiency becomes high. In the case of sensorless control that does not detect the field direction of the motor, there is a method of calculating the d-axis current id from the δ-axis and γ-axis currents of the inverter that can be calculated based on the motor constant (induced voltage constant) (for example, Patent Document 1).

  Further, in the IPM motor where Ld <Lq, torque can also be generated by the second term of the formula (1). In consideration of this reluctance torque, it has also been proposed to table the combinations of id and iq and refer to them according to the torque command and the rotational speed (for example, Patent Document 2). With this control, torque can be generated with the least current, and the control is highly efficient. There is also a technique for controlling similar control from the viewpoint of the magnitude of reactive power in an inverter instead of a direct current value like id and iq (for example, Patent Document 3).

  Further, in a permanent magnet type synchronous motor driven without using a speed sensor or a position sensor, the magnetic pole position of the rotor is not directly detected by a magnetic pole position sensor or the like. The magnet type synchronous motor may step out. Therefore, in order to prevent overcurrent and abnormal vibration caused by the step-out, it is necessary to quickly detect the step-out and stop the operation.

  Conventionally, there is the following as to the step-out detection of such a permanent magnet type synchronous motor. For example, Patent Document 4 discloses a technique for determining step-out by calculating an effective value and a power factor of a current flowing through a synchronous motor. Patent Document 5 discloses a technique for determining a step-out by comparing a current cycle of a synchronous motor with a cycle of a drive voltage. Furthermore, Patent Document 6 discloses a technique for determining step-out using an AC component averaging of dq axis current of a synchronous motor.

JP 2000-232800 A JP 2000-32799 A JP 2000-262089 A Japanese Patent Laid-Open No. 9-294390 JP 2001-25282 A JP 2003-79183 A

  However, in the above technique, since control is basically performed while referring to a two-dimensional table of id and iq, there is a problem that the table becomes large. In addition, when a current component parallel to the magnetic flux vector, reactive power, or the like is obtained, the configuration becomes complicated and a burden is imposed on the arithmetic processing.

  In addition, regarding the out-of-step determination, in the method described in Patent Document 4 described above, it is difficult to determine the effective current value for determining out-of-step, and the out-of-step is erroneous even when driving in an overload state. There is a risk of detection. Further, according to the method of Patent Document 5, step-out detection is impossible if there is no difference between the synchronous motor current cycle and the voltage cycle of the driving device. Moreover, in the said patent document 6, the process of extracting the alternating current component of dq axis | shaft current, detecting these averages or only a specific frequency component, etc. was needed, and there existed a problem that control became a little complicated. .

  The present invention has been made in view of the above, and an object of the present invention is to provide a permanent magnet type synchronous motor control apparatus and method that can be controlled with high efficiency with a simple configuration and with a minimum current. . It is another object of the present invention to provide a permanent magnet type synchronous motor control device and method for easily detecting step-out.

  In order to solve the above-described problems and achieve the object, a permanent magnet type synchronous motor control device according to the present invention includes means for setting voltage commands proportional to the motor frequency in two axes of a rotation rectangular coordinate system, and 2 Means for converting the voltage command of the shaft into three phases, means for applying the three-phase voltage command to the motor through power conversion by an inverter, and the motor terminal without detecting the field direction of the motor In a controller for a permanent magnet type synchronous motor having means for feeding back current, power factor angle determining means for determining a power factor angle from the feedback current and converting the motor terminal current obtained in three phases into orthogonal coordinates Power factor angle adjusting means for adjusting the power factor angle to the rotation angle used at the time is provided.

  Since φ (i) can be treated as a function of the current I, I is obtained using the fed δ-axis and γ-axis currents, and φ derived therefrom is added or subtracted from the rotation axis θ of the three-phase / two-phase conversion. Then, the current that has undergone the three-phase / two-phase conversion with the adjusted angle as the rotation axis is negatively fed back to the speed command, which is the frequency multiplied by the gain, to the motor power factor angle φ that is the minimum current for torque generation. The voltage command is modified to match.

  The control device for the permanent magnet type synchronous motor includes a coordinate conversion means for performing coordinate conversion of the feedback current into an excitation current component and a torque current component, and when the state where the excitation current component exceeds a specified value continues for a predetermined period. And a step-out detecting means for detecting step-out of the permanent magnet type synchronous motor. Alternatively, the control device for the permanent magnet type synchronous motor includes coordinate conversion means for converting the feedback current into an excitation current component and a torque current component, an integration means for integrating the excitation current component, and an excitation current component. There may be provided a step-out detecting means for detecting step-out of the permanent magnet type synchronous motor when the state where the integral value is equal to or greater than the prescribed integration value continues for a predetermined period.

  According to the above configuration, the step-out is detected based on the excitation current component used for the motor control, so the step-out detection can be easily performed.

  It is preferable that the specified value used in the step-out detection means is updated according to the temperature. In the permanent magnet type synchronous motor, the amount of magnetic flux changes due to a change in motor temperature. That is, if the temperature is high, the amount of magnetic flux decreases and the excitation current component also decreases. Therefore, the out-of-step detection accuracy can be further improved by updating the specified value according to the temperature.

  The present invention relates to a process of setting a voltage command proportional to the frequency of the motor in two axes of a rotation rectangular coordinate system, a process of coordinate-converting the voltage command of the two axes into three phases, and converting the voltage command of the three phases into an inverter The process of applying to the motor through power conversion by the process, the process of feeding back the motor terminal current without detecting the field direction of the motor, the process of determining the power factor angle from the feedback current, and three phases There is provided a control method for a permanent magnet type synchronous motor, characterized by comprising a power factor angle adjusting process for adjusting the power factor angle to a rotation angle used when converting the obtained motor terminal current into orthogonal coordinates.

In the control method, when the feedback current is converted into an excitation current component and a torque current component, and the state where the excitation current component is a predetermined value or more continues for a predetermined period, the permanent magnet synchronous motor It is preferable that the method includes a step of detecting a step-out of. Alternatively, the control method includes a step of converting the feedback current into an excitation current component and a torque current component, a step of integrating the excitation current component, and an integrated value of the excitation current component being a specified value or more. And detecting a step-out of the permanent magnet type synchronous motor when the operation continues for a predetermined period.
In this way, step-out detection can be easily performed by using the excitation current component used for motor control.

The permanent magnet type synchronous motor control device according to the present invention has an effect that it is possible to control the permanent magnet type synchronous motor with a simple configuration and high efficiency with a minimum current.
Furthermore, the permanent magnet type synchronous motor control device according to the present invention has an effect that the motor step-out can be easily detected.

  Hereinafter, embodiments of a permanent magnet type synchronous motor control device according to the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment.

  FIG. 1 is a functional block diagram showing a control device for a permanent magnet type synchronous motor according to an embodiment of the present invention. In the figure, ωm is the rotational speed command, n is the number of pole pairs of the motor, ω1 is the inverter output frequency (primary frequency), vδ * and vγ * are the δ-axis and γ-axis voltage commands, vu *, vv *, and vw *, respectively. Are u-phase, v-phase, and w-phase voltage commands, vu, vv, and vw are u-phase, v-phase, and w-phase output voltages, respectively, iu, iv, and iw are u-phase, v-phase, and w-phase, respectively. The output currents i δ and i γ are inverter output currents of the δ axis and the γ axis, respectively, i δ is an excitation current component, and i γ is a torque current component. θ is the output voltage phase, and φ is the power factor angle.

  The apparatus 1 includes a speed command calculation unit 2, a voltage command calculation unit 3, a 2-phase / 3-phase conversion unit 4, an inverter 5, a 3-phase / 2-phase conversion unit 6, and a power factor angle calculation unit 8. Here, for simplicity, the inverter 5 includes a PWM circuit. The motor 7 is finally driven by the voltage applied from the inverter 5.

  The present invention is characterized by the voltage command calculation means 3, the power factor angle calculation means, and the three-phase / two-phase conversion means 6. In the voltage command calculation means 3, the δ-axis current iδ after the three-phase / two-phase conversion of the currents iu, iv, and iw of u, v, and w calculated from the output voltage of the inverter 5 and the inverter output frequency ω1, The δ-axis voltage command vδ * and the γ-axis voltage command vγ * are obtained by the following formulas (2-1) and (2-2) using the proportionality constant K, the d-axis induced voltage coefficient Λd, and the proportional gain K. .

  Hereinafter, control when the voltage command calculation means 3 is represented by the above equations (2-1) and (2-2) will be described. First, in order to help understanding, a case where the power factor angle φ (i) is 0 will be described. Since φ is a power factor angle, when the phase difference between the voltage applied to the motor 7 and its current is 0, the power factor represented by cos φ is 1. Therefore, this control is so-called power factor 1 control.

In the voltage command calculation by the above formulas (2-1) and (2-2), for example, if the γ-axis voltage command vγ * is smaller than the motor terminal voltage, the δ-axis inverter output current iδ is negative in order to weaken the field. become. On the other hand, if vγ * is large, the field becomes stronger and iδ is positive.
Specifically, in the calculation of the equation (2-1), the δ-axis voltage command performs negative proportional control so that the δ-axis current iδ becomes zero. Thus, if there is a positive or negative fluctuation of i δ, the voltage command v δ * is determined so as to quickly eliminate the fluctuation of i δ by the gain Kδ.

  The γ-axis voltage command vγ * is set to a voltage value that compensates for the voltage of Λdω1 corresponding to the induced voltage, and in order to perform an operation for setting the δ-axis current iδ to 0, here, integral control for integrating iδ is performed. I do. That is, in the calculation of Expression (2-2), if the δ-axis current iδ accumulates with either positive or negative value, a voltage value that returns to the original value with a larger value is determined. Although integral control is used here, proportional control, proportional integral control, or the like may be used depending on control responsiveness.

  By doing so, iδ becomes 0, and when iδ becomes 0, vδ also becomes 0. Eventually, the current passed through the motor 7 and the motor applied voltage are only γ-axis components, and the phase coincides, so that the power factor is 1. This alone minimizes the product of voltage and current and enables power-saving control.

  However, in the IPM motor, the reluctance torque that is the second term of the formula (1) can also be used. Therefore, the current can be further reduced by using both the magnet torque and the reluctance torque in a balanced manner. When the motor current (absolute value obtained by combining the δ axis and the γ axis) I flows with an advance angle θ with respect to the induced voltage, the d-axis current id and the q-axis current iq are expressed by the equations (3-1) and (3-2). ).

  The condition for maximizing the motor torque τ with respect to the motor current I is θ of τ (formula (4-1)) obtained by substituting formulas (3-1) and (3-2) into formula (1). The derivative with respect to is zero. If this is made into Formula (4-2), it will become as follows.

  When I · sin θ and I · cos θ in the above equation (4-2) are expressed by id and iq in the equations (3-1) and (3-2), the following equation (5) is obtained.

Equation (5) is an equation representing the relationship of (id + A) ² -iq ² = A ^{2 where} A = Λd / 2 (Ld−Lq), where id is the vertical axis and iq is the horizontal axis. It becomes a graph as shown in.

  Therefore, the figure shows the combination of id and iq when the minimum current is reached. However, since the relationship between id and iq includes a square root, a table for use in control is used. This method is required.

  Therefore, the inventor diligently investigated whether it was possible to control by the phase difference between the motor current I and the motor applied voltage V from a different viewpoint. First, since φ is the difference between the phase of the motor applied voltage V and the phase of the motor current I, it is expressed by the following equation (6).

As described above, the relationship between id and iq at the minimum current is (id + A) ² −iq ² = A ² , which is a hyperbola, and therefore, according to the hyperbolic function (sinh, cosh), the following equation (7-1) ) And (7-2).

When α is sufficiently small and can be regarded as 0, it can be approximated as id = Aα ² and iq = Aα, respectively. Further, vd and vq obtained by capturing the voltage applied to the motor on the d-axis and the q-axis can be regarded as the following expressions (8-1) and (8-1) from an equivalent expression of the motor circuit. This is because the resistance is negligible at the normal operation speed.

  Using these equations, the phase difference φ in equation (6) can be approximated as in the following equation (9).

Here, since the current I can be expressed by the following equation (10), the phase difference φ is eventually expressed by the following equation (11). That is, it has been found that the phase difference φ is substantially proportional to the current. Further, iδ = 0 by the control, and I is proportional to iγ, so that the phase difference φ is also proportional to iγ.
FIG. 3 shows the relationship between the phase difference φ and the current I obtained by plotting using the d-axis current and the q-axis current without approximation as described above. Even in such a case, it is almost proportional, and the validity of control using the proportional relationship can be understood.

  As described above, the inventor has found that the control of the minimum current required for generating the torque can be realized by positively controlling the power factor angle (phase difference) instead of φ = 0. In view of this, in the present invention, as shown in FIG. 1, power factor angle adjusting means is provided that sets the rotation axis used when the current of the motor terminal is converted to three-phase / two-phase to θ-φ instead of θ. . Since φ is a function of the current I, as shown in the figure, first, I is obtained using the fed back γ-axis current (iδ is controlled to 0). When I is obtained, φ is obtained by multiplying it by a constant. Thus, φ is subtracted from the rotation axis θ of the three-phase / two-phase conversion.

  Then, the current subjected to the three-phase / two-phase conversion with θ-φ as the rotation axis is negatively fed back to the speed command nω *, which is a frequency multiplied by the gain Kω9, so that the synchronous motor operates stably. Is fixed. This is because the load increases and the current increases when the rotor position is delayed relative to the rotating magnetic field. Conversely, the load decreases and the current decreases as the rotor position advances relative to the rotating magnetic field. It stabilizes by correcting. (2-1) and (2-2) are controlled so that vδ = Iδ = 0, so that the phase used for current three-phase / 2-phase conversion and voltage two-phase / 3-phase conversion is used. Are different, the difference φ is controlled to be the power factor angle.

Since the relationship between the current I and the phase difference φ is a proportional relationship, an appropriate proportionality constant may be selected to derive φ through calculation, or accuracy in a large current value range may be obtained. For example, the relationship between I and φ may be tabulated. Even in the case of adopting a table configuration, there is an advantage that it is not necessary to take fine table data because it is almost proportional.
Even in this case, unlike referring to a two-dimensional table that is a combination of i δ and i γ, I can be obtained by actual feedback, so φ can be uniquely determined, and an appropriate phase difference φ can always be obtained. Can be sought.

  As described above, according to the control device for a permanent magnet type synchronous motor according to the present invention, the torque of the permanent magnet type synchronous motor can be controlled with the minimum current in consideration of the reluctance torque of the IPM motor. In addition, since the torque control with the minimum current can be performed only by changing the rotation axis angle at the time of the three-phase / two-phase conversion without requiring a complicated calculation, the configuration becomes simple and the maintainability is improved. Further, in the present invention, as shown in FIG. 4, the torque range in which the V / f control is appropriate is expanded with respect to the case of the power factor 1 control, and simple V / f control from the low speed rotation to the high speed rotation is the key. However, it is possible to operate with a minimum current.

  If such control becomes possible, it can contribute to size reduction and power saving of industrial products. For example, a motor for a compressor of an air conditioner is strongly demanded to save power because the air conditioner is a device that consumes a large amount of power together with a request for downsizing. Permanent magnet type synchronous motors have been adopted as one of the manifestations. However, if minimum current control can be achieved with a compact configuration according to the present invention, the above requirements will be met.

Next, a motor step-out detection method performed by the permanent magnet synchronous motor control device according to the embodiment of the present invention described above will be described.
As described above, the permanent magnet type synchronous motor according to the present embodiment is controlled so that vδ = 0 as shown in the equations (2-1) and (2-2). In the control method according to the present embodiment, for stabilization of control, the deviation from the δ-axis current command value iδ * is integrated, and the voltage commands vδ and vγ are determined so as to cancel the deviation. Therefore, in the normal operation state, the γ-axis voltage offset value Vγofs (= K∫iδdt) converges to a substantially constant value.
FIG. 5 shows a waveform at the time of starting the permanent magnet type synchronous motor in a normal state. In FIG. 5, the waveform of the γ-axis voltage offset value Vγofs, the δ-axis current iδ, and the motor current waveform (U phase) is shown from the top. As shown in this figure, during normal operation, both the γ-axis voltage offset value Vγofs and the δ-axis current iδ converge to zero.

On the other hand, when the step-out occurs, the δ-axis current iδ increases, and a strong field state is obtained. FIG. 6 shows a waveform at the time of starting the permanent magnet type synchronous motor in the step-out state. In FIG. 6, the waveforms of the γ-axis voltage offset value Vγofs, the δ-axis current iδ, and the motor current waveform (U phase) are shown from the top. As shown in this figure, it can be seen that in the step-out state, the γ-axis voltage offset value Vγofs and the δ-axis current iδ are increased.
Therefore, in the step-out detection method according to the present embodiment, step-out is detected by detecting an increase in the δ-axis current i δ or the γ-axis voltage offset value Vγofs.

Specifically, the step-out is detected when a state where the δ-axis current iδ is equal to or greater than a specified value continues for a predetermined period. This makes it possible to detect the motor step-out very easily. Here, the specified value and the predetermined period are values that can be arbitrarily set according to the characteristics of the motor.
Further, the step-out may be detected using a γ voltage offset value Vγofs which is an integral value of the δ-axis current instead of the δ-axis current iδ. Specifically, when the γ voltage offset value Vγofs is equal to or greater than a specified value, preferably, the step-out is detected when a state where the γ voltage offset value Vγofs is equal to or greater than the specified value continues for a predetermined period. Also good.

  Generally, in a synchronous motor, a pull-in operation is performed by forced synchronous operation when starting up. During the forced synchronous operation, the δ-axis current iδ does not converge to zero. Therefore, if only the δ-axis current iδ is monitored as described above, there is a possibility of erroneous detection of step-out. Even in such a case, by using the γ voltage offset value Vγofs, which is an integral value of the δ-axis current iδ, it is possible to prevent erroneous detection of step-out and improve step-out detection accuracy.

  As described above, according to the control device of the present embodiment, detection of motor step-out is performed using at least one of the γ-axis voltage offset value Vγofs and the δ-axis current iδ used for motor control. Therefore, it is possible to realize step-out detection very easily.

  Furthermore, in the step-out detection method according to the present embodiment, the specified value may be updated according to the temperature in consideration of a change in the magnetic flux amount due to the motor temperature. For example, when the temperature rises, the amount of magnetic flux decreases, so the δ-axis current iδ decreases. Conversely, when the temperature decreases, the amount of magnetic flux increases, so the δ-axis current iδ increases. Therefore, by setting the specified value high when the temperature rises and setting the specified value low when the temperature decreases, it is possible to further increase the accuracy of step-out detection.

  Note that the γ-axis voltage offset value Vγofs also varies depending on the change in the amount of magnetic flux of the motor. FIG. 7 to FIG. 9 show changes in each state quantity at the start-up when the magnetic flux quantity is changed in a normal state, that is, in a state where no step-out has occurred. 7 shows the state quantities when the magnetic flux amount is normal, FIG. 9 shows the case where the magnetic flux amount is increased, and FIG. 8 shows the respective state quantities when the magnetic flux amount is intermediate between FIGS. 7 to 9, the γ-axis voltage offset value Vγofs, the δ-axis current iδ, and the motor current waveform (U phase) are respectively shown from the top.

  Thus, even if no step-out occurs, the γ-axis voltage offset value Vγofs increases or decreases according to the amount of magnetic flux. Therefore, when only the change of the γ-axis voltage offset value Vγofs is detected, it is difficult to distinguish whether the change is caused by a step-out or a change in the amount of magnetic flux. There is. However, even in such a case, the step-out and the electromagnetic state can be distinguished by the combination of the γ-axis voltage offset value Vγofs and the inverter output power.

In other words, when the amount of magnetic flux of the motor increases, even if the γ-axis voltage offset value Vγofs increases, the inverter output takes a value corresponding to the operation state at that time, whereas when the step-out occurs, γ When the shaft voltage offset value Vγofs increases, the output power decreases because it does not work as an inverter, and falls below a specified value.
Therefore, if the state where the γ-axis voltage offset value Vγofs is equal to or greater than the specified value continues for a predetermined period and the state where the inverter output power is equal to or less than the specified value continues for the predetermined period, it is determined that the step-out has occurred. It is possible to avoid erroneous detection due to variation in quantity. In addition to the inverter output power, it is also possible to make a determination based on the effective value of the motor current or the like.

In addition, in the control method of the permanent magnet type synchronous motor according to the above-described embodiment, examples of the method for detecting the inverter output current include the following.
For example, in the case of a drive device for a permanent magnet type synchronous motor having a configuration as shown in FIG. 10, detection by three shunt resistors 13 inserted in the lower arm portion 12 of the inverter 11, and between the converter 14 and the inverter 11. Any configuration of detection by the inserted DC shunt resistor 15 and detection by the current sensor 18 inserted between the inverter 11 and the motor 7 can be used.

  The control device for a permanent magnet type synchronous motor according to the present invention is useful for minimum current control of a permanent magnet type synchronous motor, and is particularly suitable for minimum current control of an IPM motor.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the specific structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.

It is a block diagram which shows the system configuration | structure which concerns on one Embodiment of this invention. It is a graph which shows the relationship between the d-axis current and the q-axis current at the minimum current, the vertical axis is the d-axis current, and the horizontal axis is the q-axis current. It is a graph which shows the relationship between the electric current when it becomes the minimum electric current, and a phase difference, a vertical axis | shaft is a phase difference and a horizontal axis is an electric current. It is a graph which shows the current-torque characteristic in the case of power factor 1 control, and the case of this invention, a vertical axis | shaft is an electric current and a horizontal axis is a torque. The waveform at the time of starting of a permanent magnet type synchronous motor in a motor normal state is shown. The waveform at the time of starting of a permanent magnet type synchronous motor in a motor step-out state is shown. The waveform at the time of starting of a permanent magnet type | mold synchronous motor in the case of a motor normal state and a magnetic flux amount in a normal state is shown. The waveform at the time of starting of a permanent magnet type synchronous motor when a motor is in a normal state and the amount of magnetic flux is slightly increased from a normal state is shown. The waveform at the time of starting of a permanent-magnet-type synchronous motor in the case of a motor normal state and increasing the magnetic flux amount further than the magnetic flux amount of FIG. It is a figure which shows an example of the drive device of a permanent magnet type | mold synchronous motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Apparatus 2 Speed command calculating means 3 Voltage command calculating means 4 Phase converting means 5 Inverter 6 Phase converting means 7 Motor 8 Power factor angle calculating means I Motor current id d-axis current iq q-axis current V Motor applied voltage vγ γ-axis voltage command vδ δ-axis voltage command Λd induced voltage coefficient τ motor torque φ power factor angle

Claims (8)

Means for setting a voltage command proportional to the frequency of the motor in two axes of a rotation rectangular coordinate system;
Means for coordinate-converting the voltage command of the two axes into three phases;
Means for applying the three-phase voltage command to the motor through power conversion by an inverter;
In a control device for a permanent magnet synchronous motor having means for feeding back the motor terminal current without detecting the field direction of the motor,
Power factor angle determining means for determining a power factor angle from the feedback current;
A control apparatus for a permanent magnet type synchronous motor, comprising: power factor angle adjusting means for adjusting the power factor angle to a rotation angle used when the motor terminal current obtained in three phases is converted into orthogonal coordinates. Coordinate conversion means for converting the feedback current into an excitation current component and a torque current component;
The permanent magnet type synchronization according to claim 1, further comprising a step out detection means for detecting step out of the permanent magnet type synchronous motor when the state where the excitation current component is equal to or greater than a predetermined value continues for a predetermined period. Motor control device.   The control device for a permanent magnet type synchronous motor according to claim 2, further comprising updating means for updating the specified value according to temperature. Coordinate conversion means for converting the feedback current into an excitation current component and a torque current component;
Integrating means for integrating the exciting current component;
2. The permanent detection according to claim 1, further comprising: a step-out detection unit that detects step-out of the permanent magnet type synchronous motor when a state where the integral value of the exciting current component is equal to or greater than a predetermined integral value continues for a predetermined period. Control device for magnet synchronous motor.   The control device for a permanent magnet type synchronous motor according to claim 4, further comprising updating means for updating the specified value according to temperature. A process of setting a voltage command proportional to the motor frequency in two axes of a rotation rectangular coordinate system;
A process of coordinate-converting the voltage command of the two axes into three phases;
Applying the three-phase voltage command to the motor through power conversion by an inverter;
The process of feeding back the motor terminal current without detecting the field direction of the motor;
Determining a power factor angle from the feedback current;
A control method for a permanent magnet type synchronous motor, comprising: a power factor angle adjusting process for adjusting the power factor angle to a rotation angle used when the motor terminal current obtained in three phases is converted into orthogonal coordinates. Converting the feedback current into an excitation current component and a torque current component;
The control of a permanent magnet type synchronous motor according to claim 6, further comprising a step of detecting a step-out of the permanent magnet type synchronous motor when the state where the excitation current component is equal to or greater than a predetermined value continues for a predetermined period. Method. Converting the feedback current into an excitation current component and a torque current component;
Integrating the excitation current component;
The permanent magnet type synchronization according to claim 6, further comprising a step of detecting a step-out of the permanent magnet type synchronous motor when a state in which the integral value of the excitation current component is equal to or greater than a predetermined value continues for a predetermined period. Motor control method.

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