JP5786203B2 - Power converter control device, motor characteristic measuring method, and program - Google Patents

Description

  The present invention relates to a power converter control device, a motor characteristics measuring method, and a program that can be applied when measuring a motor characteristic of an AC motor by controlling a power converter that converts power supplied to the AC motor.

In general, an AC electric motor that rotationally drives a rolling roller that moves a steel plate to a rolling mill is mainly driven by vector control. Here, in order to perform vector control of an AC motor using the vector control device, it is necessary to set control constants necessary for vector control based on motor constants specific to the AC motor to be controlled. For this reason, the operator acquires the design value of the motor constant in advance, and sets the control constant after calculating the motor constant based on the measurement results of various resistance measurement tests, no-load tests, and restraint tests. The motor constant includes, for example, a primary resistance (r ₁ ) that is a DC resistance on the primary side, a secondary resistance (r ₂ ′) that is a DC resistance on the secondary side, and a combined resistance of primary and secondary (rσ = r _1). + R ₂ ′), and primary and secondary combined leakage inductance (Lσ = L ₁ + L ₂ ′). In addition, since it is necessary to set the rated torque current and the rated excitation current for vector control of the AC motor, in the following description, the motor constant and the rated torque current and excitation current characteristics described later are collectively referred to as “motor”. It will be called "characteristic".

  By the way, even if it is the AC motor of the same standard, the error of a motor constant may arise for every product, However, The operation | work which calculates a motor constant for every 1 unit | set was complicated. For this reason, a technique that can automatically calculate the motor constant and set the control constant has been demanded. For example, in Patent Literature 1, various measurement conditions are given in a state where an AC motor is connected to the power conversion unit control device, and a control constant is set based on the motor constant calculated according to the AC voltage command value and the current detection value. Is disclosed.

  Patent Document 2 discloses a method for calculating an electric motor constant using a power converter control device. In the technique described in Patent Document 2, a voltage having an arbitrary frequency is applied to the AC motor while the AC motor is stopped, and the relationship between the voltage value of the applied voltage and the detected current value taken out from the PWM inverter. The control constant is set by calculating the motor constant from

  Further, Patent Document 3 gives the primary angular frequency command value and the primary voltage command value to the power converter control device, and the mutual inductance of the AC motor based on the detected current value detected from the AC motor operating in a steady state. A technique for computing is disclosed.

JP-A-62-262697 JP 7-55899 A JP-A-6-265607

  By the way, when driving an AC motor whose motor constant is unknown, the characteristics of the AC motor can be grasped only from information (hereinafter referred to as “nameplate information”) written on a nameplate attached to the casing of the AC motor. There is a case. This nameplate information is generally described only for characteristics such as rated frequency, rated voltage, and rated current. For this reason, it has been difficult to set the rated torque current and the rated excitation current from the nameplate information.

  In addition, field weakening control may be performed in the operating range in which the AC motor is normally operated. In this case, since the AC motor has a magnetic saturation characteristic (hereinafter abbreviated as “saturation characteristic”), it is necessary to change the excitation current in consideration of the influence of magnetic saturation to weaken the field. However, in this field weakening control, it is difficult to set the excitation current for each speed of the AC motor.

  The object of the present invention is to calculate the motor constant of the AC motor, calculate the rated torque current and the rated excitation current, which are control constants necessary for vector control of the AC motor, and the excitation current when performing field weakening control. It is to be able to set from limited information by a simple method.

In order to achieve the above object, in the present invention, the first coordinate conversion unit converts the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command into a three-phase AC voltage command, and the pulse generation unit includes a three-phase voltage command. According to the AC voltage command, the voltage and frequency of AC power input from the AC power source are converted, and a pulse signal for controlling the power converter that drives the AC motor is generated. Next, based on the primary angular frequency command, the d-axis excitation current and the q-axis torque current are output from the power conversion unit detected by the current detection unit by the second coordinate conversion unit. Convert to Then, the motor characteristic measurement unit outputs the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command to the first coordinate conversion unit, so that the ratio between the voltage and the frequency that the power conversion unit outputs to the AC motor In the first measurement mode in which the motor characteristics of the AC motor are measured based on the d-axis excitation current and the q-axis torque current, which are input from the second coordinate converter, the primary of the AC motor is controlled. From the result of measuring the resistance, measuring the combined resistance and combined leakage inductance of the AC motor in the second measurement mode, and calculating the excitation inductance, rated torque current and rated excitation current of the AC motor in the third measurement mode , and requests the motor characteristics of the ac motor.
Here, according to the first aspect of the present invention, in the third measurement mode, the top speed of the AC motor is made constant, the ratio of the voltage and frequency applied to the AC motor is changed, and the second coordinate transformation is performed. Repeating the control to bring the voltage calculation value at the top speed calculated based on the d-axis excitation current and the q-axis torque current input from the unit close to the rated voltage used as a criterion,
When the voltage calculation value matches the rated voltage, determine the excitation inductance of the AC motor at the top speed, set the d-axis excitation current as the rated excitation current,
A rated torque current calculated from the rated excitation current is set, and the rated excitation current and the rated torque current are obtained as motor characteristics of the AC motor at the top speed.
According to the second aspect of the present invention, in the third measurement mode, the frequency at which the base speed of the AC motor is kept constant is maintained, the ratio of the voltage and frequency applied to the AC motor is changed, and the AC motor is Change the field to drive,
Repeating the control of bringing the voltage calculation value at the base speed calculated based on the d-axis excitation current and the q-axis torque current input from the second coordinate converter close to the determination reference voltage,
When the voltage calculation value matches the judgment reference voltage, determine the excitation inductance and excitation current of the AC motor at the base speed,
The excitation inductance and the excitation current are obtained as the motor characteristics of the AC motor at the base speed.
According to the third aspect of the present invention, in the third measurement mode, a frequency that makes the base speed of the AC motor constant is maintained,
Judging by calculating the magnetic flux calculation value calculated by changing the voltage and frequency ratio applied to the AC motor and driving the AC motor by changing the field at the ratio of the base speed and the top speed from the magnetic flux at the top speed. Control close to the reference magnetic flux,
The excitation inductance and excitation current of the AC motor when the calculated magnetic flux value matches the determination reference magnetic flux are obtained as the motor characteristics of the AC motor at the base speed.
According to the 4th viewpoint of this invention, in the 3rd measurement mode, the frequency which makes the base speed of AC motor constant is maintained,
Judging by calculating the magnetic flux calculation value calculated by changing the voltage and frequency ratio applied to the AC motor and driving the AC motor by changing the field at the ratio of the base speed and the top speed from the magnetic flux at the top speed. If the d-axis excitation current input from the second coordinate converter exceeds the excitation current limiter in the process of making the control close to the reference magnetic flux, the speed of the AC motor is changed between the base speed and the top speed. ,
When the calculated magnetic flux value matches the criterion magnetic flux calculated from the magnetic flux at the top speed at the ratio of the changed speed and the top speed, the changed speed is set as the base speed, and the excitation inductance and excitation current of the AC motor are set at the base speed. Obtained as the motor characteristics of an AC motor.

According to the present invention, the power conversion unit is controlled to change the ratio of the voltage and frequency output to the AC motor. Then, the input from the second coordinate conversion unit, based on the torque current of the excitation current and q-axis of the d-axis, in the first to third measurement mode, it is possible to determine the motor characteristics of the ac motor. For this reason, for example, by automatically setting the rated torque current and the rated excitation current from the limited information obtained from the nameplate information, the time required to drive the AC motor is greatly reduced, and appropriate control constants are used. It becomes possible to perform vector control of the AC motor.

It is a block diagram which shows the internal structure of the power converter control apparatus in the 1st Example of this invention. It is a block diagram which shows the internal structure of the electric motor characteristic measurement part in the 1st Example of this invention. It is a flowchart which shows the example of the 1st-3rd measurement mode (mode1-3) switched when the motor characteristic measurement part in the 1st Embodiment of this invention measures the motor characteristic of an AC motor. It is explanatory drawing which shows the example which changes V / f ratio, setting it as the rated frequency f1 in the _1st Example of this invention. Example of processing for calculating rated torque current IT, exciting current Id, and exciting inductance Lm ′ while operating the AC motor at a constant V / f speed at the rated speed (top speed) in the first embodiment of the present invention. It is a flowchart to show. It is explanatory drawing which shows a mode that a V / f ratio is changed and a voltage is measured, operating an alternating current motor at V / f constant speed in the base speed in the 2nd Example of this invention. It is explanatory drawing which shows the relationship between the voltage, magnetic flux, and exciting current at the time of drive | operating the alternating current motor in the 2nd Example of this invention by field weakness. It is explanatory drawing which shows the example of the saturation characteristic of the alternating current motor in the 2nd Example of this invention. It is explanatory drawing which shows the relationship of the voltage measured when the AC motor in the 2nd Example of this invention changes V / f ratio, operating V / f constant speed, exciting inductance, and exciting current. It is a flowchart which shows the relationship between the exciting current Id and magnetic flux calculation value (PHI) measured by operating an alternating current motor by V / f constant speed in the base speed in the 2nd Example of this invention. It is a block diagram which shows the internal structure of the electric motor characteristic measurement part in the 3rd Example of this invention. It is explanatory drawing which shows the relationship between the exciting current Id and magnetic flux calculation value (PHI) measured by operating an alternating current motor by V / f constant speed in the base speed in the 3rd Example of this invention. 12 is a flowchart showing an example of processing for determining an excitation inductance LmB ′ and an excitation current IdB at a base speed when the V / f constant speed operation of the AC motor is performed at the base speed in the third embodiment of the present invention. . It is explanatory drawing which shows the relationship between magnetic flux (PHI) and exciting current Id at the time of the field weakening driving | operation obtained from the magnetic flux saturation characteristic in the 3rd Example of this invention. It is explanatory drawing which shows the relationship between the exciting current Id and magnetic flux calculation value (PHI) measured by operating an alternating current motor at V / f constant speed in the base speed in the 4th Example of this invention. It is explanatory drawing which shows the relationship between the exciting current Id and magnetic flux calculation value (PHI) measured by operating an alternating current motor by V / f constant speed between the base speed and the top speed in the 4th Example of this invention. An example of processing for determining the excitation inductance LmB ′ and the excitation current IdB at the base speed by operating the AC motor at a constant V / f speed between the base speed and the top speed in the fourth embodiment of the present invention. It is a flowchart to show. It is explanatory drawing which shows the example of the saturation characteristic of the alternating current motor in the 4th Example of this invention.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. In the present embodiment, an AC motor control system 10 in which the motor constant and the control constant can be obtained based on the motor characteristics of the AC motor 3 driven by AC power will be described. The AC motor control system 10 is a motor that measures a motor characteristic including at least a rated torque current and a rated excitation current by calculating a motor constant of the AC motor 3 in cooperation with internal blocks to be described later when a computer executes a program. Realize characteristic measurement method.

FIG. 1 is a block diagram showing the internal configuration of the AC motor control system 10.
The AC motor control system 10 includes an AC power source 1 that outputs AC power, a power converter 2 that converts AC power input from the AC power source 1 into AC power and voltage of a desired frequency, and outputs the power. And a power converter control device 4 that controls the operation. In addition, the AC motor control system 10 is configured to switch between a current detection unit 5 that outputs a detection value of an alternating current output from the power conversion unit 2, an input unit 6 through which an operator inputs nameplate information, and various modes that will be described later. The switching unit 18 and the AC motor 3 are provided. The power conversion unit 2 includes a switching element such as a transistor, and is configured by a pulse width modulation (PWM) inverter or the like. Furthermore, the name plate information input operator from the input unit 6, for example, the capacity of the AC motor 3 P (Watts), rated frequency f _1, the rated voltage V _1, there is the rated current I _1.

  The power conversion unit control device 4 includes a motor characteristic measurement unit 15 that measures the motor characteristics of the AC motor 3. The motor characteristic measurement unit 15 outputs the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command to the first coordinate conversion unit 12, so that the voltage and frequency output from the power conversion unit 2 to the AC motor are output. Control to change the ratio. Then, the motor characteristic measuring unit 15 sets a rated torque current and a rated excitation current for driving the AC motor 3 at a rated frequency and a rated voltage as a motor constant of the AC motor 3.

  The power conversion unit control device 4 includes a vector control unit 11 and a control constant calculation unit 16. The vector control unit 11 calculates various commands to be output to the AC motor 3 so that the output torque and speed of the AC motor 3 satisfy desired motor characteristics, and performs vector control of the AC motor 3. The control constant calculation unit 16 outputs a control constant calculated based on the motor constant input from the motor characteristic measurement unit 15 to the vector control unit 11.

The power conversion unit control device 4 includes a switching unit 17 that switches the input from the motor characteristic measurement unit 15 or the vector control unit 11 and a first coordinate conversion unit 12. The first coordinate conversion unit 12 performs coordinate conversion of the d-axis voltage command Vdref and the q-axis voltage command Vqref into a three-phase AC voltage command based on the primary angular frequency command ω ₁ ref input from the switching unit 17.

  In addition, the power conversion unit control device 4 includes a pulse generation unit 13 that outputs a pulse signal to the power conversion unit 2. The pulse generation unit 13 generates a pulse signal according to a three-phase AC voltage command input from the first coordinate conversion unit 12. Then, the power conversion unit 2 that drives the AC motor 3 by controlling the on or off of the switching elements constituting the power conversion unit 2 by converting the voltage and frequency of the AC power input from the AC power source 1 by this pulse signal. Can be controlled. This pulse signal is calculated so that the value of the AC voltage output from the power converter 2 matches the value of the three-phase AC voltage command output from the first coordinate converter 12.

In addition, the power conversion unit control device 4 includes a second coordinate conversion unit 14. Based on the primary angular frequency command ω ₁ ref input from the switching unit 17, the second coordinate conversion unit 14 sets the detected value of the alternating current output by the power conversion unit 2 detected by the current detection unit 5 to d The shaft excitation current Id and the q-axis torque current Iq (hereinafter also abbreviated as “Id, Iq”) are converted. Then, the second coordinate conversion unit 14 outputs the converted Id and Iq to the motor characteristic measurement unit 15. The electric motor characteristic measurement unit 15 obtains the electric motor characteristic of the AC motor 3 based on Id and Iq input from the second coordinate conversion unit 14.

Next, a specific operation example of each unit will be described.
The power converter control device 4 drives the AC motor 3 by controlling the power converter 2. At this time, the power converter control device 4 calculates the motor characteristics by calculating the motor constant of the AC motor 3 and sets the rated torque current and the rated excitation current of the AC motor 3.

  The power converter control device 4 controls the power converter 2 so that the value of the AC voltage output from the power converter 2 matches the three-phase AC voltage command value output from the first coordinate converter 12. Then, the current detection unit 5 outputs the detected value of the AC current detected from the AC power output from the power conversion unit 2 to the second coordinate conversion unit 14.

  Here, the motor characteristic measuring unit 15 applies a predetermined AC voltage and AC frequency to the AC motor 3 in the first to third measurement modes (respectively expressed as mode1 to mode3) for measuring the motor characteristics of the AC motor 3. Thus, the power conversion unit 2 is controlled. Detailed processing examples will be described later for the first to third measurement modes. Then, the motor characteristic measuring unit 15 has characteristics of a motor constant, a rated torque current, and a rated excitation current necessary for controlling the AC motor 3 at a rated voltage and a rated frequency (hereinafter also referred to as “excitation current characteristics”). Measure.

In addition, the motor characteristic measurement unit 15 outputs a measurement signal for measuring the motor characteristics in the first to third measurement modes. This measurement signal includes a primary angular frequency command ω ₁ ref, a d-axis voltage command Vdref, a q-axis voltage command Vqref, and the like. At this time, the motor characteristic measurement unit 15 determines the motor constant based on Id and Iq input from the second coordinate conversion unit 14 and the primary angular frequency command ω ₁ ref output to the first coordinate conversion unit 12. Obtain the rated torque current and excitation current characteristics.

  The control constant calculation unit 16 performs vector control based on the motor constant obtained from the motor characteristics such as the motor constant, the rated torque current, and the excitation current characteristic calculated by the motor characteristic measurement unit 15 in the vector control mode in which the AC motor 3 is vector-controlled. The control constant of the unit 11 is calculated. The vector control unit 11 includes a primary angular frequency command, a d-axis voltage command, and a q-axis voltage generated based on Id and Iq input from the second coordinate conversion unit 14 and a control constant input from the control constant calculation unit 16. In response to the command, the power converter 2 is controlled in vector by the AC motor 3.

When measuring the motor constant, the rated torque current, and the excitation current characteristic, the power conversion unit control device 4 switches the input to the switching unit 17 from the vector control unit 11 to the motor characteristic measurement unit 15. Then, the motor characteristic measuring unit 15 provides the AC motor 3 with measurement signals in which the measurement conditions are variously changed in the first to third measurement modes. At this time, the motor characteristic measurement unit 15 outputs the primary angular frequency command ω ₁ ref, the d-axis voltage command Vdref, and the q-axis voltage command Vqref changed based on the measurement conditions to the first coordinate conversion unit 12. On the other hand, when the AC motor 3 is subjected to vector control, the power conversion unit control device 4 switches the input to the switching unit 17 from the motor characteristic measurement unit 15 to the vector control unit 11 and performs vector control of the AC motor 3 with an appropriate control constant. To do.

  Then, the switching unit 17 outputs the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command input from the motor characteristic measuring unit 15 in the first to third measurement modes to the first coordinate conversion unit 12. . On the other hand, the switching unit 17 switches the input so that the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command input from the vector control unit 11 in the vector control mode are output to the first coordinate conversion unit 12.

  FIG. 2 is a block diagram showing an internal configuration of the motor characteristic measuring unit 15. In FIG. 2, the configuration other than the motor characteristic measurement unit 15 in the AC motor control system 10 is illustrated in a simplified manner.

The motor characteristic measuring unit 15 switches the primary angular frequency command ω ₁ ref, the d-axis voltage command Vdref, and the q-axis voltage command Vqref when measuring the motor constant, rated torque current, and rated excitation current characteristics of the AC motor 3. The control part 20 output to 17 is provided. A mode switching unit 18 is connected to the control unit 20, and each command to the control constant calculation unit 16 or the switching unit 17 is switched by switching the vector control mode or the first to third measurement modes. In addition, nameplate information is input to the control unit 20 from the input unit 6. In addition, Id and Iq data are input to the control unit 20 from the second coordinate conversion unit 14.

  In addition, the motor characteristic measurement unit 15 includes an excitation current measurement unit 21 that measures excitation current from Id and Iq data, an excitation inductance measurement unit 22 that measures excitation inductance Lm ′, and a rated torque current that calculates a rated torque current. A calculation unit 23 is provided. The exciting inductance measuring unit 22 measures the exciting inductance Lm ′ from the relationship between the current and voltage applied to the AC motor 3. The rated torque current calculation unit 23 calculates the rated torque current from Id and Iq input from the second coordinate conversion unit 14 using a calculation formula described later.

  In addition, the motor characteristic measurement unit 15 includes a rated voltage calculation unit 24. The rated voltage calculation unit 24 calculates the rated voltage calculation value V of the AC motor 3 by changing the measurement voltage while keeping the voltage / frequency V / f ratio applied to the AC motor 3 constant. In the following description, the voltage / frequency ratio of the AC power supply 1 output to the AC motor 3 is referred to as “V / f ratio”. The operation of the AC motor 3 with the V / f ratio kept constant is referred to as “V / f constant speed operation”.

In addition, the motor characteristic measurement unit 15 includes a measurement condition determination unit 25. Measurement condition determining unit 25 determines the rated voltage calculation value V is, the measurement condition of the AC motor 3 at the time that matches the nominal voltages V ₁ obtained from the nameplate information. The rated voltage calculation unit 24 calculates the rated voltage calculation value V based on the rated voltage V ₁ input from the nameplate information by the operator and input from the input unit 6 and Id and Iq input from the rated torque current calculation unit 23. To do. The measurement condition determination unit 25 determines the measurement conditions of the AC motor 3 when the rated voltage V ₁ matches the rated voltage calculation value V, and obtains the rated excitation current and the rated torque current, thereby determining the rated operation of the AC motor 3. Is realized.

  Then, the measurement condition determination unit 25 notifies the control unit 20 of the rated excitation current and the rated torque current under the determined measurement condition. When the operation of the AC motor 3 is controlled, the control unit 20 outputs the notified rated excitation current and rated torque current to the control constant calculation unit 16. Thereafter, the vector control unit 11 performs vector control of the AC motor 3 by outputting the control constant calculated by the control constant calculation unit 16 to the vector control unit 11.

  FIG. 3 shows an example of first to third measurement modes (modes 1 to 3) that are switched when the motor characteristic measuring unit 15 measures the motor characteristics of the AC motor 3 and that measures the motor characteristics of the AC motor 3. It is a flowchart.

  First, the operator operates the input unit 6 to input the nameplate information of the AC motor 3 in advance to the control unit 20 of the motor characteristic measuring unit 15 (step S1) and use it in the first to third measurement modes. The nameplate information includes a setting range of a plurality of measurement voltages (Vmode1 (1), Vmode1 (2)...) Applied to the AC motor 3, a reference for the AC current detection value, a calculation reference for the rated torque current IT, and measurement. Used when setting criteria for conditions.

Then, the switching unit 17 is switched to the first measurement mode, it performs a single-phase DC excitation to the AC motor 3, to measure the value of primary resistance r ₁ of the AC motor 3 (step S2). In the first measurement mode, the control unit 20 includes, as measurement conditions, a primary angular frequency command ω ₁ ref = 0, a q-axis voltage command Vqref = 0, a d-axis voltage command Vdref, and a plurality of measurement voltages (Vmode1 (1), Vmode1 (2)...) Are set and given to the AC motor 3. Then, the control unit 20 outputs the d-axis voltage command Vdref to the first coordinate conversion unit 12. Thereafter, the power converter 2 applies a measurement voltage obtained by converting the d-axis voltage command Vdref to the AC motor 3.

At this time, the second coordinate conversion unit 14 converts the detected value of the alternating current detected by the current detection unit 5 into Id and Iq, and outputs the converted value to the motor characteristic measurement unit 15. The motor characteristic measuring unit 15 is configured to determine the primary voltage of the AC motor 3 based on the relationship between the measurement voltage applied to the AC motor 3 and Id and Iq converted from the AC current output from the power conversion unit 2 corresponding to the measurement voltage. It calculates the value of the resistor _{r 1.}

Next, the switching unit 17 switches to the second measurement mode and performs single-phase AC excitation on the AC motor 3 (step S3). In the second measurement mode, the control unit 20 uses, as measurement conditions, a primary angular frequency command ω ₁ ref = 0, a q-axis voltage command Vqref = 0, and a d-axis voltage command Vdref for performing single-phase AC excitation as a sine wave. The measured voltage (Vmode2 × sin (ωmode2 × t)) is applied to the AC motor 3. Then, the control unit 20 outputs a d-axis voltage command Vdref as a sine wave measurement voltage to the first coordinate conversion unit 12. Thereafter, the power converter 2 applies a measurement voltage obtained by converting the d-axis voltage command Vdref to the AC motor 3.

The motor characteristic measurement unit 15 determines the combined resistance rσ (= r ₁ + r ₂ ′) of the AC motor 3 based on the relationship between the voltage applied to the power conversion unit 2 and Id and Iq converted from the AC current output from the power conversion unit 2. ), The value of the combined leakage inductance Lσ (= L1 + L2 ′) is calculated.

Next, the switching unit 17 switches to the third measurement mode, operates the AC motor 3 while keeping the top speed of the AC motor 3 constant and keeping the V / f ratio constant (step S4). In the third measurement mode, the control unit 20 sets the d-axis voltage command Vdref = 0, the primary angular frequency command ω ₁ ref = ω ₁ mode 3, and the q-axis voltage command Vqref = Vmode 3 as measurement conditions, and V / f constant speed. A voltage command for operation is output to the first coordinate conversion unit 12. Then, the control unit 20 outputs the measurement voltage to the first coordinate conversion unit 12. Thereafter, the power conversion unit 2 applies a measurement voltage obtained by converting a voltage command for performing a V / f constant speed operation to the AC motor 3.

The motor characteristic measurement unit 15 calculates the voltage calculation value V at the top speed based on the relationship between the voltage applied to the power conversion unit 2 to calculate the motor constant and Id and Iq input from the second coordinate conversion unit 14. Is calculated. Then, the voltage calculation value V, repeated control closer to the rated voltages V ₁ used as a criterion. Then, when the voltage calculation value V in the top speed is equal to the rated voltage V _1, to confirm the exciting inductance Lm 'in the top speed, the exciting current Id in the d-axis is set to the rated exciting current, the rated exciting current Id Set the calculated rated torque current IT. Then, the excitation inductance Lm ′, the rated torque current, and the rated excitation current of the AC motor 3 are obtained as the motor characteristics of the AC motor 3 at the top speed, and the excitation current characteristics considering the influence of magnetic flux saturation are obtained.

  Finally, the control constant calculation unit 16 calculates a control constant using the calculated motor constant, rated torque current, and excitation current characteristics (step S5), and writes the control constant in a memory (not shown). After the above process is completed, the electric motor characteristic measurement unit 15 ends the first to third measurement modes. Then, the switching unit 17 switches from the measurement mode to the vector control mode, and the vector control unit 11 drives the AC motor 3 at a variable speed by vector control.

  Next, a processing example for measuring the rated torque current and the excitation current characteristic in the third measurement mode performed in step S4 of FIG. 3 will be described.

  In order to perform vector control of the AC motor 3, it is necessary to determine the rated torque current (q-axis current Iq) and the rated excitation current (d-axis current Id) on the orthogonal d-axis and q-axis. However, when the design value of AC motor 3 cannot be acquired in advance, the information of AC motor 3 is limited to nameplate information. In order to carry out vector control of such an AC motor 3, motor constants are calculated according to the flowchart of FIG. 3 described above, and control constants used for vector control are set. However, conventionally, it has been difficult to appropriately set the rated torque current IT and the excitation current Id.

In the present embodiment, as shown in step S4 of FIG. 3, the AC inductance 3 is operated at a constant V / f speed to measure the excitation inductance Lm ′. In this measurement, the rated torque current IT and the rated excitation current IdT are set as follows. Here, the V / f constant speed operation of the AC motor 3 is performed using the rated frequency f ₁ at the top speed obtained from the nameplate information, thereby measuring the excitation inductance LmT ′ and the d-axis excitation current IdT at the top speed. . In the following description, the excitation inductance Lm ′ measured at the top speed (also referred to as “maximum rotation speed”) of the AC motor 3 is represented as “LmT ′”, and the d-axis excitation current Id is represented by “IdT”. It expresses. The excitation inductance Lm ′ measured at the base speed (also referred to as “base rotation speed”) of the AC motor 3 is represented as “LmB ′”, and the d-axis excitation current Id is represented as “IdB”.

As described above, the excitation inductance Lm ′ has already been measured from the relationship between the current and voltage applied to the AC motor 3 by the excitation inductance measurement unit 22. The rated torque current calculation unit 23, the rated current I ₁ read from the nameplate information, using the measured excitation current IDT, the following equation (1), calculates the rated torque current IT.

Here, in order to calculate the appropriate rated torque current IT and rated excitation current IdT at the top speed of the AC motor 3, it is necessary to determine the measurement conditions necessary for performing the V / f constant speed operation. In this embodiment, as a criterion for determining a measurement condition, using the nominal voltages V ₁ read from nameplate data.

Therefore, the rated voltage calculation unit 24 measures r ₁ measured in the _first measurement mode, the combined leakage inductance Lσ measured in the second measurement mode, the excitation inductance LmT ′ at the top speed measured in the third measurement mode, the rating Using the torque current IT and the rated excitation current IdT, the rated voltage calculation value V is calculated from the voltage equations shown in the following equations (2), (3), and (4). The rated voltage calculation value V is calculated as Vd and Vq for the d-axis and q-axis, respectively, and then calculated by the sum of squares of Vd and Vq.
Vd = r ₁ × IdT−ω ₁ × Lσ × IT (2)
Vq = r ₁ × IT + ω ₁ × Lσ × IdT + ω ₁ × LmT ′ × IdT
= R ₁ × IT + ω ₁ × (Lσ + LmT ′) × IdT (3)

Here, ω ₁ = ωr + ωs. The slip frequency ωs is measured in the first measurement mode, the primary resistance r ₁ measured in the first measurement mode, the combined resistance rσ measured in the second measurement mode, and the third measurement mode. It is calculated from the excitation inductance LmT ′.

Next, an example of changing the V / f ratio while maintaining the rated frequency f ₁ will be described.
FIG. 4 is an explanatory diagram showing an example of changing the V / f ratio by changing the voltage V while keeping the rated frequency f ₁ at the top speed constant.

The V / f ratio is obtained by changing the measurement voltage while keeping the rated frequency f ₁ (ω ₁ ref = ω ₁ mode 3 = 2 × π × f ₁ ) of the power output from the power conversion unit 2 to the AC motor 3 constant. And the rated voltage calculation value V is calculated. In this example of the embodiment, the q-axis voltage command Vqref = Vmode3 a measurement condition in the third measurement mode change, the rated voltage calculation value V selects a measured value in the measurement condition that matches the rated voltages V ₁ .

Next, an example of arithmetic processing performed in the third measurement mode switched in step S4 of FIG. 3 will be described in detail.
FIG. 5 is a flowchart showing an example of processing for calculating the rated torque current IT, the exciting current Id, and the exciting inductance Lm ′ while operating the AC motor at a constant speed of V / f at the rated speed (top speed).

First, the control unit 20 of the motor characteristic measurement unit 15 includes the rated frequency f ₁ , the rated voltage V ₁ , the rated current I ₁ , the primary resistance r ₁ measured in the first measurement mode, and the second measurement mode. The measured combined resistance rσ and combined leakage inductance Lσ are taken in (step S11).

Next, the control unit 20 performs the V / f constant speed operation of the AC motor 3 in the third measurement mode (step S12). At this time, the control unit 20 sets the d-axis voltage command Vdref = 0, the primary angular frequency command ω ₁ ref = ω ₁ mode 3 (= 2 × π × f ₁ ) as the measurement conditions, and the q-axis voltage command Vqref is initialized. Set to the value Vini. The initial value Vini, for example the rated voltages V ₁ obtained from the name plate information is set. Then, the control unit 20 outputs a voltage command for performing the V / f constant speed operation to the power conversion unit 2. Thereby, the power converter 2 applies the measurement voltage to the AC motor 3 so that the AC motor 3 performs the V / f constant speed operation.

  Next, the current detection unit 5 detects an alternating current in the third measurement mode output from the power conversion unit 2, and the second coordinate conversion unit 14 outputs Id and Iq data. Then, the exciting current measuring unit 21 takes in the data of Id and Iq from the second coordinate conversion unit 14 (step S13).

Next, the excitation inductance measuring unit 22 inputs each parameter to the function F for obtaining the excitation inductance LmT ′, and calculates the value of the excitation inductance LmT ′ of the AC motor 3 (step S14). These parameters include the primary resistance r ₁ , the combined leakage inductance Lσ, the primary angular frequency command ω ₁ ref, the q-axis voltage command Vqref captured at step S11, and Id and Iq captured at step S13.

Then, the rated torque current calculation unit 23, a data Id fetched in step S13, in accordance with (1) the rated current _{I 1} acquired at step S11, calculates the rated torque current IT. Further, the slip frequency ωs is calculated from the primary resistance r ₁ and the combined resistance rσ captured in step S11, the excitation inductance Lm ′ calculated in step S14, the excitation current Id, and the rated torque current IT according to the above-described equation (5). To do. Furthermore, the motor characteristic measuring unit 15 calculates the rated frequency ω ₁ = 2 × π × f ₁ + ωs (step S15).

Next, the rated voltage calculation unit 24 calculates the rated voltage calculation value V based on the expressions (2), (3), and (4) (step S16). Next, the measurement condition determination unit 25 compares the rated voltage calculation value V with the rated voltage V ₁ (V ₁ / √3 in the case of line voltage) of the nameplate information captured in step S11 (step S17).

In the case where the rated voltage calculation value V is larger than the nominal voltages _{V 1} is, q-axis voltage command Vqref set in step S12 (e.g., 385V) decreases voltage Vstep (eg, 5V) from subtracted (step S18), and step The process returns to S12. Then repeats steps S12~S18 to the rated voltage calculation value V is equal to the rated voltage _{V 1.}

On the other hand, when the rated voltage calculation value V is equal to the rated voltage V _1, the measurement condition determining unit 25 ends the measurement of the motor characteristics. In this case, the measurement condition determining unit 25 'rated magnetizing inductance LMT' excitation inductance Lm of the measurement conditions rated voltage calculation value V coincides with the nominal voltages V ₁ and the exciting current Id and the rated excitation current IDT. Further, the torque current calculated from the rated excitation current IdT is determined as the rated torque current IT (step S19), and the determined value is written in a memory (not shown). This value is read from the control constant calculation unit 16 in the vector control mode and used for calculation of the control constant.

According to the motor characteristic measuring unit 15 in the first embodiment described above, the AC motor 3 is rated with the rated voltage V ₁ and the rated current I ₁ obtained from the nameplate information in the first to third measurement modes. In order to operate, the motor constant, the rated excitation current IdT, and the rated torque current IT are automatically selected. For this reason, in the vector control mode, the control constant calculation unit 16 sets the control constant based on the calculated electric motor characteristics and switches to vector control to operate the AC motor 3 at the rated operation as described in the nameplate information. Can be performed.

Further, the motor characteristic measuring section 15, the voltage calculation value V in the top speed, until it matches the rated voltage V _1, the voltage applied to the AC motor 3 is increased from a value lower than the rated voltage V _1, or, the rated voltage repeatedly performing control to decrease from V _1. This makes it possible to obtain a voltage calculation value V close to the rated voltage V _1.

Here, it starts to determine the rated voltage calculation value V from a voltage higher than the rated voltages V ₁ in FIG. 5, to the rated voltage calculation value V is equal to the nominal voltages V _1, and decreasing the measured voltage. Conversely, for example, the setting of the V / f ratio starting from a half of the rated voltage V _1, to the rated voltage calculation value V is equal to the rated voltage V _1, as well increasing the measured voltage Measurement conditions can be determined.

In addition, the value of the primary resistance used for the calculations of Equations (2), (3), and (5) is set in consideration of the temperature rise during normal operation with respect to the numerical values measured at room temperature. For this reason, the value of the primary resistance that changes as the temperature of the AC motor 3 rises is taken into the calculation of the voltage calculation value V at the top speed. Thus, the motor constant at the top speed and the rated voltage V ₁ and the current value calculated from the rated operation during the normal operation match the rated voltage V ₁ and the rated current I ₁ obtained from the nameplate information. The rated excitation current IdT and the rated torque current IT can be selected.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS.
FIG. 6 is an explanatory diagram showing a state in which measurement is performed by changing the V / f ratio while operating the AC motor 3 at a constant V / f speed at the base speed. The process of performing the V / f constant speed operation at the base speed is a modification of the process shown in step S4 of FIG.

  When the AC motor 3 is driven with field weakening, the excitation current Id is changed between the base speed and the top speed on the basis of the value of the excitation current IdT at the top speed determined in FIG. An excitation current IdB is obtained.

  FIG. 7 is an explanatory diagram showing the relationship between the top speed and base speed, voltage, magnetic flux, and excitation current when the AC motor 3 is operated with field weakening. FIG. 7A shows an example of a voltage Vemf (= ωre × Φ) called a speed electromotive force, FIG. 7B shows an example of a magnetic flux Φ in field weakening, and FIG. 7C shows an excitation current IdB at a base speed and an excitation current IdT at a top speed. Each example is shown.

  As shown in FIG. 7B, the voltage Vemf increases in proportion to the speed (FIG. 7A) because the magnetic flux Φ is constant until the base speed is increased (field strengthening). Further, as shown in FIG. 7B, the magnetic flux Φ is decreased (field weakening) so as to be inversely proportional to the speed from the base speed to the top speed. When field weakening is performed in this way, the voltage Vemf becomes constant, and the AC motor 3 has constant output characteristics between the base speed and the top speed (FIG. 7A).

  At this time, the magnetic flux Φ is obtained as “Φ = Lm ′ × Id”. Therefore, when the excitation inductance Lm ′ is constant, the excitation current Id changes in inverse proportion to the speed in accordance with the change of the magnetic flux Φ as shown by the solid line in FIG. 7C. Then, based on the rated excitation current IdT at the top speed determined in the first embodiment described above, the excitation current characteristics from the base speed to the top speed shown by the solid line in FIG. 7C can be determined.

FIG. 8 is an explanatory diagram illustrating an example of saturation characteristics of the AC motor 3.
When the magnetic flux Φ of the AC motor 3 has a saturation characteristic, the magnetic flux Φ in the field weakening region (unsaturation point) becomes the magnetic flux ΦT = LmT ′ × IdT at the top speed, and in the field strengthening region (saturation point). The magnetic flux Φ becomes magnetic flux ΦB = LmB ′ × IdB at the base speed. Here, the excitation inductance is LmB ′ <LmT ′. Therefore, if the magnetic flux Φ has a saturation characteristic, the excitation current characteristic from the base speed to the top speed needs to be set larger than the solid line excitation current Id, as shown by the broken line in FIG. 7C. Further, since the magnetic flux Φ is saturated, it is necessary to set an appropriate value of the excitation current Id so that the useless excitation current Id does not flow to the AC motor 3.

  Therefore, in the present embodiment, as shown in FIG. 6, the change in the excitation current characteristic due to the saturation of the magnetic flux Φ is performed by performing the V / f constant speed operation of the AC motor 3 in the third measurement mode at the base speed. Is measuring.

  FIG. 9 is an explanatory diagram showing the relationship of the voltage, excitation inductance, and excitation current with respect to the top speed and the base speed when the AC motor 3 is operated at a constant V / f speed and the V / f ratio is changed. 9A shows the relationship of the voltage V with respect to the speed, FIG. 9B shows the relationship of the excitation inductance Lm ′ with respect to the speed, and FIG. 9C shows the relationship of the excitation current Id with respect to the speed.

  As shown in FIG. 9A, the control unit 20 of the motor characteristic measuring unit 15 increases the voltage applied to the AC motor 3 from the low V / f ratio at the top speed until the high V / f ratio at the base speed. . When the magnetic flux Φ becomes a non-saturation point (field weakening) between the base speed and the top speed, the excitation inductance Lm ′ becomes substantially constant as shown by the solid line in FIG. 9B. For this reason, as shown by a solid line in FIG. 9C, the excitation current characteristic between the base speed and the top speed has a relationship inversely proportional to the speed. It is also possible to calculate and set the rated excitation current IdB measured at the base speed from the rated excitation current IdT measured at the top speed.

  On the other hand, when the AC motor 3 is saturated with the magnetic flux Φ, the excitation inductance Lm ′ changes as shown by the broken line in FIG. 9B. At this time, the excitation inductance Lm ′ decreases as the V / f ratio becomes higher in the field strengthening region, and an excessive excitation current IdB flows to the AC motor 3 as shown by the broken line in FIG. 9C. For this reason, it is necessary to measure the excitation current IdB and the excitation inductance LmB ′ that are appropriate values when the AC motor 3 is operated at the base speed. Therefore, the motor characteristic measuring unit 15 in the second embodiment performs the V / f constant speed operation in the third measurement mode shown in FIG. 6 at the base speed, thereby exciting current characteristics due to saturation of the magnetic flux Φ. Is measuring the change.

  When measuring the exciting current characteristics, as shown in the first embodiment, the control unit 20 performs the V / f constant speed operation of the AC motor 3 at the rated point of the top speed. Then, after calculating the rated torque current IT and the excitation current IdT at the top speed, the V / f ratio is changed and the excitation current characteristic is measured. Under the same V / f ratio, the measured values of the excitation current Id and the excitation inductance Lm ′ are almost the same value. For this reason, at the base speed, measurement is started from a voltage at which the V / f ratio is lowered.

  The voltage having a low V / f ratio at the base speed is, for example, a voltage obtained from the V / f ratio under measurement conditions determined by the top speed. The reason why the measurement of the excitation current characteristic is started from a voltage with a low V / f ratio is to prevent the excitation current Id from becoming excessive due to the influence of magnetic saturation of the AC motor 3. For this reason, the measurement of the excitation current characteristic is started while applying a low measurement voltage to the AC motor 3 in a state where the V / f ratio is low.

  FIG. 10 is a flowchart showing the relationship between the excitation current Id and the magnetic flux calculation value Φ measured by operating the AC motor 3 at a constant V / f speed at the base speed. The process of performing V / f constant speed operation at this base speed is a modification of the process performed in the third measurement mode shown in step S4 of FIG.

  In the third measurement mode, the motor characteristic measurement unit 15 in the second embodiment maintains a frequency that keeps the base speed of the AC motor 3 constant, and changes the ratio of the voltage and frequency applied to the AC motor 3. Then, the AC motor 3 is driven with a weak field. And the control which makes the voltage calculation value V in the base speed calculated based on Id and Iq input from the 2nd coordinate transformation part 14 close to the rated voltage used as a criterion is repeated. Thereafter, when the voltage calculation value V matches the rated voltage, the motor characteristic measurement unit 15 determines the excitation inductance and the excitation current at the base speed, and obtains the excitation inductance and the excitation current as the motor characteristics of the AC motor 3 at the base speed. .

First, the control unit 20 includes the rated voltage V ₁ of the nameplate information, the rated torque current IT determined at the top speed, the primary resistance r ₁ measured in the first measurement mode, and the synthesis measured in the second measurement mode. The resistance rσ and the combined leakage inductance Lσ are taken in for use in the calculation (step S21).

Next, the control unit 20 sets the d-axis voltage command Vdref = 0, the primary angular frequency command ω ₁ ref = ω ₁ mode 3 (= 2 × π × fB), and the base speed as measurement conditions in the third measurement mode. And the q-axis voltage command Vqref is set to the initial value Vini. Here, fB is the frequency of the base speed. The initial value Vini may be set to a voltage that becomes a V / f ratio under measurement conditions determined by measurement at the top speed. And the control part 20 outputs the voltage command which performs a V / f constant speed operation, and applies a measurement voltage to the AC motor 3 (step S22).

  Next, the control unit 20 controls the power conversion unit 2 to apply a measurement voltage to the AC motor 3. When the current detection unit 5 detects the detection value of the alternating current, the excitation current measurement unit 21 takes in the data of Id and Iq from the second coordinate conversion unit 14 (step S23).

Subsequently, the excitation inductance measuring unit 22 uses the data of the primary resistance r ₁ , the combined leakage inductance Lσ, the primary angular frequency command ω ₁ ref, the q-axis voltage command Vqref, and Id and Iq captured in step S21 as a function F. Then, the value of the excitation inductance Lm ′ of the AC motor 3 at the base speed is calculated (step S24).

Next, the rated torque current calculator 23 receives the rated torque current IT acquired in step S21, the excitation current Id acquired in step S23, the primary resistance r ₁ and the combined resistance rσ acquired in step S21, and step S24. According to the equation (5), the slip frequency ωs is calculated from the excitation inductance Lm ′ calculated in (1) to obtain ω ₁ = 2 × π × fB + ωs (step S25).

Then, the rated voltage calculation unit 24 calculates the rated voltage calculation value V based on the equations (2), (3), and (4) (step S26). Next, the measurement condition determination unit 25 compares the rated voltage calculation value V with the rated voltage V ₁ (V ₁ / √3 in the case of line voltage) obtained from the nameplate information captured in step S21 (step S21). S27). Since the primary angular frequency ω ₁ is small at the base speed, the components of ω ₁ × Lσ × IT and ω ₁ × Lσ × IdB are small. For this reason, the measurement condition determination unit 25 uses a determination reference voltage Vα that is set so as to decrease by the speed ratio instead of the rated voltage V ₁ for comparison with the rated voltage calculation value V.

  When the rated voltage calculation value V is smaller than the determination reference voltage Vα, the increment Vstep is added to the q-axis voltage command Vqref set in step S22, and the process returns to step S22 (step S28). Then, the processes in steps S22 to S27 are repeated until the rated voltage calculation value V matches the determination reference voltage Vα. On the other hand, if it is determined in step S27 that the rated voltage calculation value V matches the determination reference voltage Vα, the measurement ends. Then, the measurement condition determination unit 25 determines Lm ′ under the measurement condition that matches the determination reference voltage Vα as the excitation inductance LmB ′ at the base speed, and Id as the excitation current IdB at the base speed (step S29).

  According to the motor characteristic measuring unit 15 in the second embodiment described above, the values of the AC voltage and the AC current output to the AC motor 3 when the AC motor 3 is rated at the base speed are at least from the nameplate information. The excitation current IdB at the motor constant and base speed is selected so as to be smaller than the obtained value. For this reason, based on the obtained motor characteristics, the control constant calculation unit 16 can set a control constant in consideration of field weakening of the AC motor 3. Further, even when the motor characteristic measurement unit 15 switches to the vector control mode and operates the AC motor 3, it is possible to perform the rated operation of the AC motor 3 without excessively increasing the excitation current and voltage.

Further, the motor characteristic measuring section 15, the voltage calculation value V in the base rate, until it matches the rated voltage V _1, the voltage applied to the AC motor 3 is increased from a value lower than the rated voltage V _1, or, the rated voltage repeatedly performing control to decrease from V _1. This makes it possible to obtain a voltage calculation value V close to the rated voltage V _1.

Also in the second embodiment, considering that the resistance value increases due to the temperature rise when the AC motor 3 is normally operated with respect to the values measured at room temperature, the equations (2), (3), ( 5) The resistance value used for the calculation of the equation is set. For this reason, the value of the primary resistance that changes as the temperature of the AC motor 3 rises is taken into the calculation of the voltage calculation value V at the base speed. Accordingly, the voltage and current at the rated operation in the normal operation while not exceed the rated voltages V ₁ obtained from the nameplate information, it can be selected and motor constants, the exciting current IdB at the base rate.

[Third embodiment]
Next, an operation example of the power conversion unit control device 4 according to the third embodiment of the present invention will be described with reference to FIGS.
The third embodiment is different from the first and second embodiments in which the voltage is used as a determination reference in that the magnetic flux is used as a determination reference. In the following description, parts already described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

FIG. 11 is a block diagram showing an internal configuration of the motor characteristic measuring unit 30 in the third embodiment.
The internal configuration of the electric motor characteristic measuring unit 30 employs almost the same configuration as the electric motor characteristic measuring unit 15 in the first embodiment described above. However, the motor characteristic measuring unit 30 in FIG. 11 is different in that a magnetic flux calculating unit 26 for calculating the magnetic flux of the AC motor 3 is used instead of the rated voltage calculating unit 24 of the motor characteristic measuring unit 15 in FIG. The magnetic flux calculation unit 26 calculates a magnetic flux Φ from the measured excitation current Id and excitation inductance Lm ′ when the AC motor 3 is operated at a constant V / f speed.

  FIG. 12 is an explanatory diagram showing an example of the relationship between the excitation current Id measured by operating the AC motor 3 at a constant V / f speed at the base speed and the magnetic flux calculation value Φ. FIG. 12A shows an example in which the measurement voltage is raised while the base speed is kept constant while the V / f ratio is high, and FIG. 12B shows an example of the characteristic of the magnetic flux Φ that varies with the excitation current Id.

As shown in FIG. 12A, the magnetic flux calculator 26 calculates the excitation current Id measured at each V / f ratio indicated by (α), (β), and (γ) and the excitation inductance Lm ′ according to the equation (6). Calculate the magnetic flux Φ.
Φ = Lm ′ × Id (6)
At this time, saturation characteristics of the magnetic flux Φ are obtained as (α), (β), and (γ) shown in FIG. 12B.

Here, as shown in FIG. 7, when the field weakening is performed, the magnetic flux Φ has a relationship that is inversely proportional to the speed from the base speed to the top speed. Therefore, the magnetic flux ΦT = LmT ′ × IdT at the top speed obtained from the excitation current IdT at the top speed and the excitation inductance LmT ′ determined in the first embodiment is calculated in advance. Then, using the following equation (7), the value of the magnetic flux ΦB at the base speed obtained by multiplying the magnetic flux ΦT by the ratio of the top speed ωreT and the base speed ωreB is calculated as the determination reference magnetic flux ΦB.
Judgment reference magnetic flux ΦB = ΦT × ωreT / ωreB (7)

  Then, the motor characteristic measuring unit 30 measures the excitation current characteristic while increasing the measurement voltage and changing the V / f ratio. At this time, the motor characteristic measurement unit 30 calculates the magnetic flux Φ from the excitation current and the excitation inductance measured at each V / f ratio, and is measured when the magnetic flux Φ matches the determination reference magnetic flux ΦB calculated by the equation (7). Exit. Then, the excitation current Id measured under the measurement conditions at the end of measurement is the excitation current IdB at the base speed, and the excitation inductance Lm ′ is the excitation inductance LmB ′ at the base speed.

Next, calculation processing performed in the third measurement mode shown in step S4 of FIG. 3 will be described.
FIG. 13 is a flowchart showing an example of processing for determining the excitation inductance LmB ′ and the excitation current IdB at the base speed when the AC motor 3 is operated at a constant V / f speed at the base speed.

  The motor characteristic measurement unit 30 in the third embodiment maintains a frequency that makes the base speed of the AC motor 3 constant in the third measurement mode. Then, the ratio of the voltage and frequency applied to the AC motor 3 is changed, and the magnetic flux calculation value Φ calculated by driving the AC motor 3 with field weakening is set to a ratio between the base speed and the top speed from the magnetic flux at the top speed. Control to bring it closer to the calculated determination reference magnetic flux ΦB is performed. Thereafter, the excitation inductance Lm ′ and the excitation current Id when the calculated magnetic flux value Φ matches the determination reference magnetic flux ΦB are obtained as the motor characteristics of the AC motor 3 at the base speed.

First, the control unit 20 of the motor characteristic measurement unit 30 uses the primary resistance r ₁ measured in the first measurement mode, the combined resistance rσ measured in the second measurement mode, and the combined leakage inductance Lσ for calculation. To capture. Further, the magnetic flux ΦB at the base speed calculated from the magnetic flux ΦT at the top speed according to the equation (7) is taken in as the determination reference magnetic flux ΦB (step S31).

Next, the control unit 20 sets the d-axis voltage command Vdref = 0, the primary angular frequency command ω ₁ ref = ω ₁ mode 3 (= 2 × π × fB) and the base speed as measurement conditions in the third measurement mode. The q-axis voltage command Vqref is set to the initial value Vini. As the initial value Vini, a voltage that becomes a V / f ratio under the measurement conditions determined by the measurement at the top speed may be set.

  Next, the control part 20 outputs the voltage command which performs a V / f constant speed operation, and applies a measurement voltage to the AC motor 3 (step S32). When the current detection unit 5 detects the detection value of the alternating current, the excitation current measurement unit 21 takes in the data of Id and Iq from the second coordinate conversion unit 14 (step S33).

Subsequently, the excitation inductance measuring unit 22 uses the data of the primary resistance r ₁ , the combined leakage inductance Lσ, the primary angular frequency command ω ₁ ref, and the q-axis voltage commands Vqref, Id, and Iq captured in step S31 as a function F. And the value of the excitation inductance Lm ′ of the AC motor 3 at the base speed is calculated (step S34).

  Then, the magnetic flux calculator 26 calculates the magnetic flux Φ according to the equation (6) from the exciting current Id acquired in step S33 and the exciting inductance Lm ′ calculated in step S34 (step S35).

  Next, the measurement condition determination unit 25 compares the calculated magnetic flux Φ with the determination reference magnetic flux ΦB at the base speed captured in step S31 (step S36). If the calculated magnetic flux Φ is smaller than the determination reference magnetic flux ΦB, the increment Vstep is added to the q-axis voltage command Vqref set in step S32 (step S37), and the process returns to step S32. Then, the processes in steps S32 to S35 are repeated until the calculated magnetic flux Φ matches the determination reference magnetic flux ΦB.

  If it is determined in step S36 that the calculated magnetic flux Φ matches the determination reference magnetic flux ΦB, the measurement is terminated. Then, the excitation inductance Lm ′ under the measurement condition that matches the determination reference magnetic flux ΦB is determined as the excitation inductance LmB ′ at the base speed, and the excitation current Id is determined as the excitation current IdB at the base speed (step S38).

  FIG. 14 is an explanatory diagram showing the relationship between the magnetic flux Φ and the excitation current Id during field weakening operation obtained from the magnetic flux saturation characteristics. 14A shows the relationship between the excitation current Id and the magnetic flux Φ, FIG. 14B shows the relationship between the speed and the magnetic flux Φ, and FIG. 14C shows the relationship between the speed and the excitation currents IdB and IdT.

As shown in FIG. 14A, it can be seen that the magnetic flux ΦB at the base speed exciting current IdB is higher than the magnetic flux ΦT at the top speed exciting current IdT.
14B shows that the magnetic flux Φ with respect to the speed is in an inversely proportional relationship between the base speed and the top speed. Further, FIG. 14C shows that between the base speed and the top speed, the excitation current Id with respect to the speed has a relationship in consideration of the effect of magnetic flux saturation.
For this reason, the excitation current characteristic between the base speed and the top speed can be determined based on the magnetic flux saturation characteristic obtained by the process of measuring the motor constant.

According to the electric motor characteristic measuring unit 30 according to the third embodiment described above, even when the AC electric motor 3 is operated with field weakening and the AC electric motor 3 has a saturation characteristic, at the base speed. Change the V / f ratio. At this time, the motor characteristic measurement unit 30 repeatedly performs control to increase the voltage applied to the AC motor 3 from a value lower than the rated voltage V ₁ until the magnetic flux calculation value Φ matches the determination reference magnetic flux ΦB, thereby calculating the magnetic flux. The magnetic flux is measured in a range where the value Φ does not exceed the judgment reference magnetic flux ΦB. Thereby, an overcurrent at the time of measurement can be prevented, and an appropriate excitation current IdB at the base speed can be determined.

Further, the motor characteristic measuring unit 15 repeatedly performs control to increase the voltage applied to the AC motor 3 from a value lower than the rated voltage V ₁ until the magnetic flux calculation value Φ matches the determination reference magnetic flux ΦB. In this process, the excitation current characteristic between the base speed and the top speed is calculated from the saturation characteristic of the magnetic flux calculation value Φ. For this reason, it is possible to set the exciting current characteristic of the exciting current Id from the magnetic flux saturation characteristic obtained in the measurement process to the base speed to the top speed. Further, even when the AC motor 3 is operated with field weakening, the excitation current Id at each speed can be set in consideration of the saturation characteristic of the magnetic flux Φ. For this reason, even if it is the AC motor 3 whose motor constant is unknown, the vector control can be easily performed with the field weakening.

[Fourth Embodiment]
Next, an operation example of the power conversion unit control device 4 according to the fourth embodiment of the present invention will be described with reference to FIGS. 15 to 18.
The power conversion unit control device 4 in the present embodiment is provided with a protection function by the excitation current limiter Idlim when performing the determination by the magnetic flux shown in the third embodiment. In other words, the fourth embodiment differs from the third embodiment in that when the measurement is limited by the excitation current limiter Idlim, the optimum base speed is determined by changing the measurement speed. Yes.

  FIG. 15 is an explanatory diagram showing an example of the relationship between the excitation current Id measured by operating the AC motor 3 at a constant V / f speed and the magnetic flux calculation value Φ at the base speed. FIG. 15A shows an example of a state in which the voltage V is increased while the base speed is constant and the V / f ratio is high, and FIG. 15B shows an example of the characteristic of the magnetic flux Φ that varies with the excitation current Id.

  Depending on the saturation characteristic of the magnetic flux Φ of the AC motor 3, there is no condition for the magnetic flux Φ to coincide with the determination reference magnetic flux ΦB as shown in FIG. 12B, and an overcurrent may flow into the AC motor 3. At this time, as shown in FIG. 15B, the excitation current Id becomes excessive before the magnetic flux Φ becomes the determination reference magnetic flux ΦB, and the excitation current IdB at the base speed cannot be specified. Here, the excitation current Id is set to a constant value so that the measured excitation current Id does not become excessive and the motor characteristic measurement unit 30 can measure the excitation current characteristic within the allowable current range of the power conversion unit 2. An exciting current limiter Idlim is set as a protective function to be suppressed. Here, the excitation current limiter Idlim is calculated by the following equation (8) in consideration of a value obtained by multiplying the allowable current Iinv of the power converter 2 by the safety factor α and multiplying the rated torque current IT by the overload factor OL. To do.

  However, if the measurement of the excitation current characteristic is limited by the excitation current limiter Idlim, the necessary magnetic flux Φ cannot be generated at the base speed due to the saturation characteristic of the AC motor 3. This means that the relationship between the voltage Vemf, the magnetic flux Φ, and the exciting current Id during the field weakening operation as shown in FIG. 7 is not established, and the constant output characteristic is not obtained between the base speed and the top speed. . Therefore, it is necessary to set the optimum base speed and the excitation current IdB at the base speed according to the saturation characteristics of the AC motor 3.

  FIG. 16 is an explanatory diagram showing an example of the relationship between the excitation current Id and the magnetic flux calculation value Φ measured by operating the AC motor 3 at a constant V / f speed between the base speed and the top speed. FIG. 16A shows an example in which the speed of the AC motor 3 is changed between the base speed and the top speed, and FIG. 16B shows an example in which the base speed excitation current IdB is determined based on the determination reference magnetic flux ΦB.

  As shown in FIG. 16A, when the measurement of the excitation current characteristic is restricted by the excitation current limiter Idlim, the motor characteristic measurement unit 30 in the fourth embodiment is an intermediate speed between the initially set base speed and top speed. The speed of the AC motor 3 is changed to a certain first intermediate speed (ωre1c). Then, the initial value of the measurement voltage is set at a point that is the same as the V / f ratio under the measurement conditions determined at the top speed. Thereafter, the motor characteristic measurement unit 30 performs measurement by gradually increasing the measurement voltage, and it matches the determination reference magnetic flux Φ1c obtained from the speed ratio calculated using the equation (7), or the excitation current limiter Idlim. To determine if the measurement is limited.

  When the excitation current characteristic measurement is limited by the excitation current limiter Idlim, the measurement is further repeated at the second intermediate speed that is the intermediate speed between the first intermediate speed (ωre1c) and the top speed shown in FIG. 16A. Conversely, when the measured magnetic flux Φ matches the determination reference magnetic flux Φ1c, the measurement is performed again at the third intermediate speed that is the intermediate speed between the initially set base speed and the first intermediate speed. Thus, the process of changing the speed is repeated, and the optimum base speed and exciting current IdB can be set by the saturation characteristics of the magnetic flux shown from the data obtained in this process.

Next, the arithmetic processing performed in the third measurement mode shown in step S4 of FIG. 3 will be described with reference to the flowchart of FIG.
FIG. 17 is a flowchart showing an example of processing for determining the excitation inductance LmB ′ and the excitation current IdB at the base speed by operating the AC motor 3 at a constant V / f speed between the base speed and the top speed.

  The electric motor characteristic measurement unit 30 maintains a frequency that makes the base speed of the AC electric motor 3 constant in the third measurement mode. Then, the ratio of the voltage and frequency applied to the AC motor 3 is changed, and the magnetic flux calculation value Φ calculated by driving the AC motor 3 with field weakening is set to a ratio between the base speed and the top speed from the magnetic flux at the top speed. Control to bring it closer to the calculated determination reference magnetic flux ΦB is performed. In this process, when the d-axis excitation current input from the second coordinate converter 14 exceeds the excitation current limiter, the speed of the AC motor 3 is changed between the base speed and the top speed. When the magnetic flux calculation value Φ matches the criterion magnetic flux calculated from the magnetic flux at the top speed by the ratio of the changed speed and the top speed, the changed speed is set as the base speed, and the excitation inductance and the excitation current are AC at the base speed. Obtained as the motor characteristics of the motor 3.

First, the control unit 20 of the motor characteristic measuring section 30 takes in order to use the combined resistance rσ measured in primary resistance r ₁ and mode 2 as measured in the first measurement mode synthesis leakage inductance Lσ to operation (step S41).

Next, as a measurement condition in the third measurement mode, the control unit 20 sets the frequency fB at the base speed to the initial value fini of the frequency command, and the primary angular frequency command ω ₁ ref = ω ₁ mode 3 (= 2 × π Xfini). Then, using the magnetic flux ΦT at the top speed, the top frequency ωreT, and the set primary angular frequency command ω ₁ ref, the determination reference magnetic flux Φr is calculated according to the equation (7) (step S42).

  Then, the control unit 20 sets the d-axis voltage command Vdref = 0 and the q-axis voltage command Vqref to the initial value Vini. The initial value Vini may be set to a voltage having a V / f ratio under measurement conditions determined by measurement at the top speed. Subsequently, the control unit 20 outputs the d-axis voltage command Vdref and the q-axis voltage command Vqref for performing the V / f constant speed operation, and applies the measurement voltage to the AC motor 3 (step S43).

  Next, when the current detection unit 5 detects an alternating current, the excitation current measurement unit 21 captures Id and Iq data from the second coordinate conversion unit 14 (step S44). Then, the measurement condition determination unit 25 compares the excitation current Id acquired in step S44 with the excitation current limiter Idlim calculated by the equation (8) (step S45).

  When the exciting current Id is larger than the exciting current limiter Idlim, the motor characteristic measuring unit 30 changes the frequency command that is the measurement condition, and accelerates the AC motor 3 (step S46). At this time, for example, after calculating the intermediate value between the top speed and the previous set value, the process returns to step S42 and the processes of steps S42 to S45 are repeated. In the following description, the speed value set last time by performing the processes from the previous steps S42 to S45 is referred to as “previous set value”, and the speed set this time by performing the processes from step S42 to S45 is referred to as “current time”. This is called “set value”. For this reason, when the process of step S46 is repeated, the intermediate value gradually approaches the top speed.

Next, when the excitation current Id captured in step S44 is less than or equal to the excitation current limiter Idlim, the primary resistance r ₁ , the combined leakage inductance Lσ captured in step S41, and the primary angular frequency command ω ₁ ref set as the measurement condition. The value of the excitation inductance Lm ′ of the AC motor 3 is calculated using the q-axis voltage command Vqref and the data of Id and Iq flowing corresponding to each voltage applied for measurement (step S47).

  Next, the motor characteristic measuring unit 30 calculates the magnetic flux calculation value Φ according to the equation (6) from the data Id acquired in step S44 and the excitation inductance Lm ′ calculated in step S47 (step S48). Then, the magnetic flux calculation value Φ is compared with the determination reference magnetic flux Φr calculated in step S42 (step S49).

  If the magnetic flux calculation value Φ is smaller than the determination reference magnetic flux Φr, the increment Vstep is added to the q-axis voltage command Vqref set in step S43 (step S50). Thereafter, the process returns to step S43, and the processes of steps S42 to S49 are repeated until the magnetic flux calculation value Φ matches the determination reference magnetic flux Φr.

  On the other hand, when it is determined in step S49 that the magnetic flux calculation value Φ matches the determination reference magnetic flux Φr, the excitation inductance Lm ′ and the excitation current Id are converted into the excitation inductance Lmc ′ and the excitation current Idc at the set measurement frequency (speed). (Step S51).

  Next, the saturation determination reference value ΔΦ / ΔId indicating the change amount of the excitation current Id with respect to the change amount of the magnetic flux calculation value Φ in the previous measurement and the current measurement is used as the saturation determination reference value and compared with the reference value dΦ ( Step S52). The saturation determination reference value ΔΦ / ΔId is a value indicating a change in magnetic flux with respect to a change in excitation current at a base speed from a value indicating a change in magnetic flux with respect to a change in excitation current at the top speed. Then, the motor characteristic measuring unit 30 changes the speed of the AC motor 3 when the value of the change in the magnetic flux with respect to the change in the d-axis excitation current measured by changing the speed of the AC motor 3 matches the saturation determination reference value. The base speed is determined, and the excitation current is determined as the excitation current at the base speed.

  Here, it is necessary to widen the field weakening range so that the exciting current does not flow unnecessarily. Here, the relationship between the excitation current Id and the magnetic flux Φ in the saturation characteristic of the AC motor 3 will be described with reference to FIG.

FIG. 18 is an explanatory diagram illustrating an example of saturation characteristics of the AC motor 3.
It is assumed that an excitation current IdB smaller than the limiter excitation current Idlim is the optimum point. Here, in the field weakening region that is the non-saturation point, the saturation determination reference value ΔΦ / ΔId≈LmT ′, and therefore the magnetic flux ΦT at the top speed can be obtained as LmT ′ × IdT.

  On the other hand, as the magnetic flux Φ is saturated, the field weakening range is widened, the excitation current Id is reduced so as not to pass unnecessary excitation current, and the excitation current is within the range of the saturation determination reference value ΔΦ / ΔId <reference value dΦ. Limit Id (0 <dΦ <LmT ′). At this time, the magnetic flux ΦB at the base speed can be obtained as LmB ′ × IdB by the excitation current IdB which is the optimum point at the base speed.

  In this way, the excitation current Id is limited so that the change amount of the magnetic flux with respect to the change of the excitation current Id indicating the degree of saturation in the saturation characteristics of the AC motor 3 does not become smaller than the reference value dΦ. By doing so, it is possible to set an optimum exciting current IdB at the base speed at the time when the amount of change in the magnetic flux becomes smaller than the predetermined determination reference magnetic flux ΦB.

  Returning to the flowchart of FIG. If it is determined in step S52 of FIG. 17 that the saturation determination reference value ΔΦ / ΔId is larger than the reference value dΦ, the frequency command that is the measurement condition is changed (step S53). For example, after calculating the intermediate value between the base speed and the previous set value, the process returns to step S42 to repeat the processes after step S43.

  If it is determined in step S52 that the saturation determination reference value ΔΦ / ΔId matches the reference value dΦ, the electric motor characteristic measurement unit 30 ends the measurement. In step S54, the speed when the condition is satisfied is set as the base speed, the excitation inductance Lm 'is determined as the excitation inductance LmB' at the base speed, and the excitation current Id is determined as the excitation current IdB at the base speed. At this time, the excitation current characteristic at the top speed can be determined from the base speed as shown in FIG. 14 from the magnetic flux saturation characteristic at each speed obtained by the measurement process.

  According to the motor characteristic measuring unit 30 according to the fourth embodiment described above, when the AC motor 3 is operated with field weakening, the excitation current IdB is set at the initial base speed by the saturation characteristic of the magnetic flux Φ. Even when it cannot be specified, the excitation current characteristic can be measured by changing the speed condition and the V / f ratio. As a result, it is possible to determine appropriate base speed and base excitation current IdB values while preventing overcurrent from flowing into the AC motor 3 during measurement. Further, it is possible to set the exciting current characteristic from the base speed to the top speed from the magnetic flux saturation characteristic obtained in the measurement process.

  Further, the motor characteristic measuring unit 30 changes the speed of the AC motor 3 and repeatedly obtains the d-axis excitation current and the magnetic flux calculation value Φ, based on the calculated saturation characteristics of the magnetic flux and the d-axis from the base speed to the top speed. The excitation current characteristics of the excitation current can be obtained.

  In the first to fourth embodiments described above, when the measurement is performed with the V / f ratio changed, the voltage is changed by fixing the frequency to the top speed or the base speed. However, the measurement may be performed by changing the frequency while fixing the voltage or changing the V / f ratio in any combination.

  The series of processes in the above-described embodiment can be executed by hardware, but can also be executed by software. When a series of processing is executed by software, it can be executed by a computer in which a program constituting the software is incorporated in dedicated hardware or a computer in which programs for executing various functions are installed. . For example, a program constituting desired software may be installed and executed on a general-purpose personal computer or the like.

  Further, a recording medium that records a program code of software that realizes the functions of the above-described embodiments may be supplied to the system or apparatus. It goes without saying that the function is also realized by reading and executing the program code stored in the recording medium by a computer (or a control device such as a CPU) of the system or apparatus.

  As a recording medium for supplying the program code in this case, for example, a flexible disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, nonvolatile memory card, ROM, etc. are used. Can do.

  Further, the functions of the above-described embodiment are realized by executing the program code read by the computer. In addition, an OS or the like running on the computer performs part or all of the actual processing based on the instruction of the program code. The case where the function of the above-described embodiment is realized by the processing is also included.

  Further, the present invention is not limited to the above-described embodiments, and various other application examples and modifications can be taken without departing from the gist of the present invention described in the claims.

  DESCRIPTION OF SYMBOLS 1 ... AC power supply, 2 ... Power conversion part, 3 ... AC motor, 4 ... Power conversion part control apparatus, 5 ... Current detection part, 6 ... Input part, 10 ... AC motor control system, 11 ... Vector control part, 12 ... 1st coordinate conversion part, 13 ... Pulse generation part, 14 ... 2nd coordinate conversion part, 15 ... Electric motor characteristic measurement part, 16 ... Control constant calculation part, 17 ... Switching part, 18 ... Mode switching part, 20 ... Control , 21 ... excitation current measurement unit, 22 ... excitation inductance measurement unit, 23 ... rated torque current calculation unit, 24 ... rated voltage calculation unit, 25 ... measurement condition determination unit

Claims (21)

A first coordinate conversion unit that converts a primary angular frequency command, a d-axis voltage command, and a q-axis voltage command into a three-phase AC voltage command;
According to the three-phase AC voltage command, a pulse generation unit that converts a voltage and frequency of AC power input from an AC power source and generates a pulse signal for controlling a power conversion unit that drives the AC motor;
Second coordinate conversion for converting the detected value of the alternating current output by the power conversion unit detected by the current detection unit into a d-axis excitation current and a q-axis torque current based on the primary angular frequency command And
By outputting the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command to the first coordinate conversion unit, the ratio of the voltage and frequency that the power conversion unit outputs to the AC motor is changed. performs control, input from said second coordinate transformation unit, on the basis of the excitation current and torque current of the q axis of the d-axis, comprising a motor characteristic measuring section for determining the motor characteristics before Symbol AC motor, a,
The motor characteristic measuring unit is
In the first measurement mode for measuring the motor characteristics of the AC motor, the primary resistance of the AC motor is measured,
In a second measurement mode for measuring the motor characteristics of the AC motor, the combined resistance and combined leakage inductance of the AC motor are measured,
In a third measurement mode for measuring the motor characteristics of the AC motor,
The top speed of the AC motor is made constant, the ratio of the voltage and frequency applied to the AC motor is changed, and the excitation current of the d-axis and the torque current of the q-axis input from the second coordinate conversion unit are changed. Repeat the control to make the voltage calculation value at the top speed calculated based on the rated voltage used as the criterion,
When the calculated voltage value matches the rated voltage, the exciting inductance of the AC motor at the top speed is determined, and the d-axis exciting current is set as the rated exciting current,
A power converter control device that sets a rated torque current calculated from the rated excitation current and obtains the rated excitation current and the rated torque current as motor characteristics of the AC motor at a top speed . The motor characteristic measurement unit increases or decreases the voltage applied to the AC motor from a value lower than the rated voltage until the voltage calculation value at the top speed matches the rated voltage. power converting unit control apparatus according to claim 1, wherein repeating the control. The power converter control device according to claim 2, wherein the motor characteristic measurement unit takes in the value of the primary resistance that changes as the temperature of the AC motor rises into the calculation of the voltage calculation value at a top speed. Further, in a vector control mode for vector control of the AC motor, a control constant calculation unit that calculates a control constant of a vector control unit that controls the operation of the AC motor based on the motor constant obtained from the motor characteristics;
The primary angular frequency command generated based on the d-axis excitation current and the q-axis torque current input from the second coordinate conversion unit, and the control constant input from the control constant calculation unit, the d-axis voltage A vector control unit that causes the power conversion unit to perform vector control of the AC motor according to a command and the q-axis voltage command;
In the first to third measurement modes, the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command input from the motor characteristic measurement unit are output to the first coordinate conversion unit, and the vector A switching unit that switches inputs so as to output the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command that are input from the vector control unit in the control mode to the first coordinate conversion unit. The power converter control device according to any one of claims 1 to 3 . A first coordinate conversion unit that converts a primary angular frequency command, a d-axis voltage command, and a q-axis voltage command into a three-phase AC voltage command;
According to the three-phase AC voltage command, a pulse generation unit that converts a voltage and frequency of AC power input from an AC power source and generates a pulse signal for controlling a power conversion unit that drives the AC motor;
Second coordinate conversion for converting the detected value of the alternating current output by the power conversion unit detected by the current detection unit into a d-axis excitation current and a q-axis torque current based on the primary angular frequency command And
By outputting the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command to the first coordinate conversion unit, the ratio of the voltage and frequency that the power conversion unit outputs to the AC motor is changed. A motor characteristic measuring unit that performs control and obtains the motor characteristic of the AC motor based on the d-axis excitation current and the q-axis torque current that are input from the second coordinate conversion unit,
The motor characteristic measuring unit is
In the first measurement mode for measuring the motor characteristics of the AC motor, the primary resistance of the AC motor is measured,
In a second measurement mode for measuring the motor characteristics of the AC motor, the combined resistance and combined leakage inductance of the AC motor are measured,
In a third measurement mode for measuring the motor characteristics of the AC motor,
Maintaining a frequency that makes the base speed of the AC motor constant, changing the ratio of voltage and frequency applied to the AC motor , driving the AC motor by changing the field,
A voltage calculation value in the excitation current and the base speed which is calculated based on the torque current of the q axis of the d-axis input from the second coordinate conversion unit repeats the control to approximate to the decision criteria voltage,
When the voltage calculation value matches the determination reference voltage, the excitation inductance and excitation current of the AC motor at a base speed are determined,
The excitation inductance and the excitation current are obtained as motor characteristics of the AC motor at a base speed.
Power conversion unit controller. The motor characteristic measurement unit, the voltage calculation value, until said match the criteria voltage increases the voltage applied to the AC motor from a value lower than the determination reference voltage, or decrease from the criterion voltage The power converter control device according to claim 5, wherein the control is repeatedly performed. The power converter control device according to claim 6, wherein the motor characteristic measurement unit takes in the value of the primary resistance that changes as the temperature of the AC motor rises into the calculation of the determination reference voltage. A first coordinate conversion unit that converts a primary angular frequency command, a d-axis voltage command, and a q-axis voltage command into a three-phase AC voltage command;
According to the three-phase AC voltage command, a pulse generation unit that converts a voltage and frequency of AC power input from an AC power source and generates a pulse signal for controlling a power conversion unit that drives the AC motor;
Second coordinate conversion for converting the detected value of the alternating current output by the power conversion unit detected by the current detection unit into a d-axis excitation current and a q-axis torque current based on the primary angular frequency command And
By outputting the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command to the first coordinate conversion unit, the ratio of the voltage and frequency that the power conversion unit outputs to the AC motor is changed. A motor characteristic measuring unit that performs control and obtains the motor characteristic of the AC motor based on the d-axis excitation current and the q-axis torque current that are input from the second coordinate conversion unit,
The motor characteristic measuring unit is
In the first measurement mode for measuring the motor characteristics of the AC motor, the primary resistance of the AC motor is measured,
In a second measurement mode for measuring the motor characteristics of the AC motor, the combined resistance and combined leakage inductance of the AC motor are measured,
In a third measurement mode for measuring the motor characteristics of the AC motor,
Maintaining a frequency that makes the base speed of the AC motor constant,
The magnetic flux calculation value calculated by changing the voltage and frequency ratio applied to the AC motor and driving the AC motor by changing the field is calculated by the ratio of the base speed and the top speed from the magnetic flux at the top speed. Control close to the determined reference magnetic flux,
Request exciting inductance及beauty magnetizing current of the AC motor in a case where the magnetic flux calculation value coincides with the criterion flux as a motor characteristic of the AC motor in the base speed
Power conversion unit controller. The motor characteristic measuring section, the magnetic flux calculation value, the criterion to match the flux, the power conversion of the AC motor a voltage applied to the repeated control to increase from a value lower than the rated voltage according to claim 8, wherein Control unit. In the process of repeatedly performing the control to increase the voltage applied to the AC motor from a value lower than the rated voltage until the magnetic flux calculation value matches the determination reference magnetic flux, the electric motor characteristic measurement unit performs the magnetic flux calculation value. The power converter control device according to claim 9, wherein an excitation current characteristic between the base speed and the top speed is calculated from the saturation characteristic of the power conversion unit. A first coordinate conversion unit that converts a primary angular frequency command, a d-axis voltage command, and a q-axis voltage command into a three-phase AC voltage command;
According to the three-phase AC voltage command, a pulse generation unit that converts a voltage and frequency of AC power input from an AC power source and generates a pulse signal for controlling a power conversion unit that drives the AC motor;
Second coordinate conversion for converting the detected value of the alternating current output by the power conversion unit detected by the current detection unit into a d-axis excitation current and a q-axis torque current based on the primary angular frequency command And
By outputting the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command to the first coordinate conversion unit, the ratio of the voltage and frequency that the power conversion unit outputs to the AC motor is changed. A motor characteristic measuring unit that performs control and obtains the motor characteristic of the AC motor based on the d-axis excitation current and the q-axis torque current that are input from the second coordinate conversion unit,
The motor characteristic measuring unit is
In the first measurement mode for measuring the motor characteristics of the AC motor, the primary resistance of the AC motor is measured,
In a second measurement mode for measuring the motor characteristics of the AC motor, the combined resistance and combined leakage inductance of the AC motor are measured,
In a third measurement mode for measuring the motor characteristics of the AC motor,
Maintaining a frequency that makes the base speed of the AC motor constant,
The magnetic flux calculation value calculated by changing the voltage and frequency ratio applied to the AC motor and driving the AC motor by changing the field is calculated by the ratio of the base speed and the top speed from the magnetic flux at the top speed. When the d-axis excitation current input from the second coordinate converter exceeds the excitation current limiter in the process of performing the control to approach the determination reference magnetic flux, the base speed to the top speed is Change the speed of the AC motor,
The magnetic flux operation value is, in a case that matches the criteria magnetic flux calculated from the magnetic flux in the top speed at a ratio of modified speed and top speed, the speed change based speed, the excitation inductance及beauty magnetizing current of said AC motor As the motor characteristics of the AC motor at the base speed
Power conversion unit controller. The motor characteristic measuring unit is
From the value indicating the magnetic flux change with respect to the change in the excitation current at the top speed, the saturation criterion value indicating the magnetic flux change with respect to the change in the excitation current at the base speed is set.
The speed of the AC motor when the value of the change in magnetic flux with respect to the change in the excitation current of the d-axis measured by changing the speed of the AC motor matches the saturation determination reference value is determined as a base speed,
Power converting unit control apparatus according to claim 1 1, wherein determining the excitation current of the excitation current in the base speed. In the process of repeatedly obtaining the excitation current and magnetic flux calculation value of the d-axis by changing the speed of the AC motor, the motor characteristic measurement unit determines the d-axis of the d-axis from the base speed to the top speed based on the calculated saturation characteristics of the magnetic flux. power converting unit control apparatus according to claim 1 wherein obtaining the exciting current characteristics of the excitation current. A step in which a first coordinate conversion unit converts a primary angular frequency command, a d-axis voltage command, and a q-axis voltage command into a three-phase AC voltage command;
A step of generating a pulse signal for controlling the power converter that drives the AC motor by converting the voltage and frequency of the AC power input from the AC power source by the pulse generator according to the three-phase AC voltage command;
Based on the primary angular frequency command, the d-axis excitation current and the q-axis excitation current are detected based on the primary angular frequency command, with the second coordinate conversion unit detected by the current detection unit. Converting to torque current;
When the motor characteristic measuring unit outputs the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command to the first coordinate conversion unit, the voltage output by the power conversion unit to the AC motor and Based on the excitation current of the d-axis and the torque current of the q-axis that are input from the second coordinate conversion unit, the control to change the frequency ratio ,
In the first measurement mode for measuring the motor characteristics of the AC motor, and measuring the primary resistance of said AC motor,
In the second measurement mode for measuring the motor characteristics of the AC motor, and measuring the combined resistance and synthetic leakage inductance of the AC motor,
In a third measurement mode for measuring the motor characteristics of the AC motor,
The top speed of the AC motor is made constant, the ratio of the voltage and frequency applied to the AC motor is changed, and the excitation current of the d-axis and the torque current of the q-axis input from the second coordinate conversion unit are changed. Repeat the control to make the voltage calculation value at the top speed calculated based on the rated voltage used as the criterion,
When the calculated voltage value matches the rated voltage, the exciting inductance of the AC motor at the top speed is determined, and the d-axis exciting current is set as the rated exciting current,
Setting a rated torque current calculated from the rated excitation current, and obtaining the rated excitation current and the rated torque current as motor characteristics of the AC motor at a top speed . A step in which a first coordinate conversion unit converts a primary angular frequency command, a d-axis voltage command, and a q-axis voltage command into a three-phase AC voltage command;
A step of generating a pulse signal for controlling the power converter that drives the AC motor by converting the voltage and frequency of the AC power input from the AC power source by the pulse generator according to the three-phase AC voltage command;
Based on the primary angular frequency command, the detected value of the alternating current output by the power conversion unit detected by the current detection unit by the second coordinate conversion unit is converted into the d-axis excitation current and the q-axis torque current. Converting, and
When the motor characteristic measuring unit outputs the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command to the first coordinate conversion unit, the voltage output by the power conversion unit to the AC motor and Based on the excitation current of the d-axis and the torque current of the q-axis that are input from the second coordinate conversion unit, the control to change the frequency ratio,
Measuring a primary resistance of the AC motor in a first measurement mode for measuring a motor characteristic of the AC motor;
Measuring the combined resistance and combined leakage inductance of the AC motor in a second measurement mode for measuring the motor characteristics of the AC motor;
In a third measurement mode for measuring the motor characteristics of the AC motor,
Maintaining a frequency that makes the base speed of the AC motor constant, changing the ratio of voltage and frequency applied to the AC motor, driving the AC motor by changing the field,
Repeating the control of bringing the voltage calculation value at the base speed calculated based on the d-axis excitation current and the q-axis torque current input from the second coordinate converter close to the determination reference voltage,
When the voltage calculation value matches the determination reference voltage, the excitation inductance and excitation current of the AC motor at a base speed are determined,
Obtaining the excitation inductance and the excitation current as motor characteristics of the AC motor at a base speed.
Method for measuring motor characteristics. A step in which a first coordinate conversion unit converts a primary angular frequency command, a d-axis voltage command, and a q-axis voltage command into a three-phase AC voltage command;
A step of generating a pulse signal for controlling the power converter that drives the AC motor by converting the voltage and frequency of the AC power input from the AC power source by the pulse generator according to the three-phase AC voltage command;
Based on the primary angular frequency command, the detected value of the alternating current output by the power conversion unit detected by the current detection unit by the second coordinate conversion unit is converted into the d-axis excitation current and the q-axis torque current. Converting, and
When the motor characteristic measuring unit outputs the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command to the first coordinate conversion unit, the voltage output by the power conversion unit to the AC motor and Based on the excitation current of the d-axis and the torque current of the q-axis that are input from the second coordinate conversion unit, the control to change the frequency ratio,
Measuring a primary resistance of the AC motor in a first measurement mode for measuring a motor characteristic of the AC motor;
Measuring the combined resistance and combined leakage inductance of the AC motor in a second measurement mode for measuring the motor characteristics of the AC motor;
In a third measurement mode for measuring the motor characteristics of the AC motor,
Maintaining a frequency that makes the base speed of the AC motor constant,
The magnetic flux calculation value calculated by changing the voltage and frequency ratio applied to the AC motor and driving the AC motor by changing the field is calculated by the ratio of the base speed and the top speed from the magnetic flux at the top speed. Control close to the determined reference magnetic flux,
Obtaining the excitation inductance and excitation current of the AC motor as the motor characteristics of the AC motor at a base speed when the calculated magnetic flux value matches the determination reference magnetic flux.
Method for measuring motor characteristics . A step in which a first coordinate conversion unit converts a primary angular frequency command, a d-axis voltage command, and a q-axis voltage command into a three-phase AC voltage command;
A step of generating a pulse signal for controlling the power converter that drives the AC motor by converting the voltage and frequency of the AC power input from the AC power source by the pulse generator according to the three-phase AC voltage command;
Based on the primary angular frequency command, the detected value of the alternating current output by the power conversion unit detected by the current detection unit by the second coordinate conversion unit is converted into the d-axis excitation current and the q-axis torque current. Converting, and
When the motor characteristic measuring unit outputs the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command to the first coordinate conversion unit, the voltage output by the power conversion unit to the AC motor and Based on the excitation current of the d-axis and the torque current of the q-axis that are input from the second coordinate conversion unit, the control to change the frequency ratio,
Measuring a primary resistance of the AC motor in a first measurement mode for measuring a motor characteristic of the AC motor;
Measuring the combined resistance and combined leakage inductance of the AC motor in a second measurement mode for measuring the motor characteristics of the AC motor;
In a third measurement mode for measuring the motor characteristics of the AC motor,
Maintaining a frequency that makes the base speed of the AC motor constant,
The magnetic flux calculation value calculated by changing the voltage and frequency ratio applied to the AC motor and driving the AC motor by changing the field is calculated by the ratio of the base speed and the top speed from the magnetic flux at the top speed. When the d-axis excitation current input from the second coordinate converter exceeds the excitation current limiter in the process of performing the control to approach the determination reference magnetic flux, the base speed to the top speed is Change the speed of the AC motor,
When the calculated magnetic flux value matches the criterion magnetic flux calculated from the magnetic flux at the top speed at the ratio of the changed speed and the top speed, the changed speed is set as the base speed, and the excitation inductance and the excitation current of the AC motor are used as the base speed. Determining as a motor characteristic of the AC motor at a speed,
Method for measuring motor characteristics . A procedure in which the first coordinate conversion unit converts the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command into a three-phase AC voltage command;
A procedure for generating a pulse signal for controlling the power conversion unit that drives the AC motor by converting the voltage and frequency of the AC power input from the AC power source according to the three-phase AC voltage command by the pulse generation unit,
Based on the primary angular frequency command, the d-axis excitation current and the q-axis excitation current are detected based on the primary angular frequency command, with the second coordinate conversion unit detected by the current detection unit. Procedure to convert to torque current,
When the motor characteristic measuring unit outputs the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command to the first coordinate conversion unit, the voltage output by the power conversion unit to the AC motor and Based on the excitation current of the d-axis and the torque current of the q-axis that are input from the second coordinate conversion unit, the control to change the frequency ratio,
In a first measurement mode for measuring the motor characteristics of the AC motor, a procedure for measuring a primary resistance of the AC motor;
In a second measurement mode for measuring the motor characteristics of the AC motor, a procedure for measuring a combined resistance and a combined leakage inductance of the AC motor;
In a third measurement mode for measuring the motor characteristics of the AC motor,
The top speed of the AC motor is made constant, the ratio of the voltage and frequency applied to the AC motor is changed, and the excitation current of the d-axis and the torque current of the q-axis input from the second coordinate conversion unit are changed. Repeat the control to make the voltage calculation value at the top speed calculated based on the rated voltage used as the criterion,
When the calculated voltage value matches the rated voltage, the exciting inductance of the AC motor at the top speed is determined, and the d-axis exciting current is set as the rated exciting current,
Setting a rated torque current calculated from the rated excitation current, and obtaining the rated excitation current and the rated torque current as motor characteristics of the AC motor at top speed,
By executing a computer program for determining the motor characteristics before Symbol AC motor. A procedure in which the first coordinate conversion unit converts the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command into a three-phase AC voltage command
A procedure for generating a pulse signal for controlling the power conversion unit that drives the AC motor by converting the voltage and frequency of the AC power input from the AC power source according to the three-phase AC voltage command by the pulse generation unit,
Based on the primary angular frequency command, the d-axis excitation current and the q-axis excitation current are detected based on the primary angular frequency command, with the second coordinate conversion unit detected by the current detection unit. Procedure to convert to torque current,
When the motor characteristic measuring unit outputs the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command to the first coordinate conversion unit, the voltage output by the power conversion unit to the AC motor and Based on the excitation current of the d-axis and the torque current of the q-axis that are input from the second coordinate conversion unit, the control to change the frequency ratio,
In a first measurement mode for measuring the motor characteristics of the AC motor, a procedure for measuring a primary resistance of the AC motor;
In a second measurement mode for measuring the motor characteristics of the AC motor, a procedure for measuring a combined resistance and a combined leakage inductance of the AC motor;
In a third measurement mode for measuring the motor characteristics of the AC motor,
Maintaining a frequency that makes the base speed of the AC motor constant, changing the ratio of voltage and frequency applied to the AC motor, driving the AC motor by changing the field,
Repeating the control of bringing the voltage calculation value at the base speed calculated based on the d-axis excitation current and the q-axis torque current input from the second coordinate converter close to the determination reference voltage,
When the voltage calculation value matches the determination reference voltage, the excitation inductance and excitation current of the AC motor at a base speed are determined,
A procedure for determining the excitation inductance and the excitation current as motor characteristics of the AC motor at a base speed;
A program for obtaining the electric motor characteristics of the AC electric motor by executing the above in a computer. A procedure in which the first coordinate conversion unit converts the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command into a three-phase AC voltage command;
A procedure for generating a pulse signal for controlling the power conversion unit that drives the AC motor by converting the voltage and frequency of the AC power input from the AC power source according to the three-phase AC voltage command by the pulse generation unit,
Based on the primary angular frequency command, the d-axis excitation current and the q-axis excitation current are detected based on the primary angular frequency command, with the second coordinate conversion unit detected by the current detection unit. Procedure to convert to torque current,
When the motor characteristic measuring unit outputs the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command to the first coordinate conversion unit, the voltage output by the power conversion unit to the AC motor and Based on the excitation current of the d-axis and the torque current of the q-axis that are input from the second coordinate conversion unit, the control to change the frequency ratio,
In a first measurement mode for measuring the motor characteristics of the AC motor, a procedure for measuring a primary resistance of the AC motor;
In a second measurement mode for measuring the motor characteristics of the AC motor, a procedure for measuring a combined resistance and a combined leakage inductance of the AC motor;
In a third measurement mode for measuring the motor characteristics of the AC motor,
Maintaining a frequency that makes the base speed of the AC motor constant,
The magnetic flux calculation value calculated by changing the voltage and frequency ratio applied to the AC motor and driving the AC motor by changing the field is calculated by the ratio of the base speed and the top speed from the magnetic flux at the top speed. Control close to the determined reference magnetic flux,
A procedure for obtaining the excitation inductance and excitation current of the AC motor as the motor characteristics of the AC motor at a base speed when the calculated magnetic flux value matches the determination reference magnetic flux,
A program for obtaining the electric motor characteristics of the AC electric motor by executing the above in a computer. A procedure in which the first coordinate conversion unit converts the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command into a three-phase AC voltage command;
A procedure for generating a pulse signal for controlling the power conversion unit that drives the AC motor by converting the voltage and frequency of the AC power input from the AC power source according to the three-phase AC voltage command by the pulse generation unit,
Based on the primary angular frequency command, the d-axis excitation current and the q-axis excitation current are detected based on the primary angular frequency command, with the second coordinate conversion unit detected by the current detection unit. Procedure to convert to torque current,
When the motor characteristic measuring unit outputs the primary angular frequency command, the d-axis voltage command, and the q-axis voltage command to the first coordinate conversion unit, the voltage output by the power conversion unit to the AC motor and Based on the excitation current of the d-axis and the torque current of the q-axis that are input from the second coordinate conversion unit, the control to change the frequency ratio,
In a first measurement mode for measuring the motor characteristics of the AC motor, a procedure for measuring a primary resistance of the AC motor;
In a second measurement mode for measuring the motor characteristics of the AC motor, a procedure for measuring a combined resistance and a combined leakage inductance of the AC motor;
In a third measurement mode for measuring the motor characteristics of the AC motor,
Maintaining a frequency that makes the base speed of the AC motor constant,
The magnetic flux calculation value calculated by changing the voltage and frequency ratio applied to the AC motor and driving the AC motor by changing the field is calculated by the ratio of the base speed and the top speed from the magnetic flux at the top speed. When the d-axis excitation current input from the second coordinate converter exceeds the excitation current limiter in the process of performing the control to approach the determination reference magnetic flux, the base speed to the top speed is Change the speed of the AC motor,
When the calculated magnetic flux value matches the criterion magnetic flux calculated from the magnetic flux at the top speed at the ratio between the changed speed and the top speed, the changed speed is set as the base speed, and the excitation inductance and excitation current of the AC motor are excited. A procedure for determining inductance and excitation current as motor characteristics of the AC motor at base speed;
A program for obtaining the electric motor characteristics of the AC electric motor by executing the above in a computer.

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