JPH11285299A - Vector controller of induction motor, and its vector control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate computational delays and adjustments of the constants of the controller of an induction motor, by computing a second secondary magnetic flux command value based on a torque command value, a first secondary magnetic flux command value, an inverter angular frequency, the constants of the induction motor, and the preset value of the input voltage of an inverter, and by performing the vector control of the induction motor through using the torque command value. SOLUTION: From a torque command value T, a secondary magnetic flux command value ϕ2, and an inverter angular frequency ωinv, the voltage command values of respective axes in the state of a vector control being established are computed. Computing a second secondary magnetic flux command value ϕ2*2 in a secondary magnetic- flux command correcting portion 1, it is outputted to a vector-control computing portion 2 to control therein an induction motor 3, based on the torque command value T and the second secondary magnetic flux command value ϕ2*2. Since the optimum secondary magnetic flux command value is computed in a feedforward manner in all the drive regions of the induction motor 3 wherein the region of its voltage being fixed is included, control delays or the adjustments of the constants of its controller are made unnecessary.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vector control apparatus and method for an induction motor, and more particularly to a technique for realizing an optimum vector control state in a fixed voltage region.

[0002]

2. Description of the Related Art In general, vector control is widely used in the industrial field as one method for controlling the output torque of an induction motor at high speed. As is well known, the vector control is generally used in an output voltage variable region in which the magnitude and phase of the output voltage can be arbitrarily changed in order to control the magnitude and phase of the output voltage.

However, depending on the application of the vector control, the operating region may be required not only in the variable output voltage region but also in a region where the output voltage is fixed. As described above, the magnitude of the voltage is changed. In the voltage fixed region where the voltage cannot be changed, the voltage phase can be changed, but the magnitude of the voltage cannot be changed, so that vector control becomes impossible in principle.

Therefore, in the voltage fixed region, so-called field-weakening control, in which the amount of magnetic flux is reduced by changing the secondary magnetic flux command in inverse proportion to the rotation speed of the induction motor, may be applied. However, in this method, even if the secondary magnetic flux command is changed as described above, the output torque of the induction motor does not match the torque command of the vector control, and the vector control state is deviated.

[0005] That is, in a region where the output voltage is fixed, unless the secondary magnetic flux command is set so that the output voltage is constant, a deviation from the vector control state occurs.

Accordingly, as one of the methods of setting the secondary magnetic flux command in the voltage fixed region, for example, a method shown in FIG. 9 has been proposed.

FIG. 9 is a block diagram for explaining the operation of the vector control device described in, for example, page 248 of the papers of the 33rd National Symposium on Use of Cybernetics in Railways. In FIG. 9, reference numeral 51 denotes a table for determining a secondary magnetic flux command Φref1 with an input of the induction motor rotation speed fr, and reference numeral 52 denotes a second magnetic flux command Φref1 and a second magnetic flux correction value ΔΦ, which is described later. A first adder 53 for calculating the secondary magnetic flux command Φref2, a vector 53 for calculating a magnetic flux component current command IdRef, a torque component current command IqRef, and a slip frequency command fs from the torque command TrqRef and the second secondary magnetic flux command Φref2 It is a control operation unit.

Reference numeral 54 denotes a voltage FF calculation unit for calculating the d-axis voltage command VdRef and the q-axis voltage command VqRef using the magnetic flux component current command IdRef and the torque component current command IqRef, and 55 denotes a d-axis voltage command VdRef and a q-axis voltage. A polar coordinate converter 56 for calculating a first voltage amplitude | V | and a voltage phase δ from the command VqRef, 56
Is a voltage fixing unit that limits the first voltage amplitude | V | by the inverter input voltage Vdc and outputs the second voltage amplitude | V | fix.
7 denotes a second voltage amplitude | V | fix and a second phase θ2 described later.
It is a PWM operation unit that calculates the switching signal of the inverter.

Reference numeral 58 denotes a first subtractor for subtracting the first voltage amplitude | V | from the second voltage amplitude | V | fix to calculate a voltage deviation ΔV. This is a magnetic flux correction value calculation unit that calculates the next magnetic flux correction value ΔΦ.

Reference numeral 60 denotes a second adder that calculates the inverter frequency finv by adding the induction motor rotation speed fr and the slip frequency command fs, 61 denotes an integrator that calculates the phase θ from the inverter frequency, and 62 denotes a phase θ and Add the voltage phase δ,
A third adder for calculating the second phase θ2; 63, a coordinate converter for calculating a torque component current Iq from the U and W phase currents Iu, Iw of the induction motor; 64, a torque component current from the torque component current command IqRef A second subtractor 65 for calculating the torque current deviation ΔIq by subtracting Iq, and a secondary resistance correction unit 65 for calculating a secondary resistance estimated value R2 ＾ from the torque current deviation ΔIq.

Next, the operation of each command of the vector control in the fixed voltage region will be described focusing on the operation. Induction motor speed
In the region where fr is equal to or lower than the frequency F1, the torque command TrqRef and the first and second magnetic flux commands Φref1 and Φref2 are constant, and the torque component current command IqRef and the magnetic flux component current command IdRef calculated by the vector control calculation unit 53 are constant. Becomes Further, the d-axis voltage command VdRef and the q-axis voltage command VqRef calculated by the voltage FFF calculation unit 54 are respectively in the negative direction,
The first voltage amplitude | V | and the second voltage amplitude | V | fix monotonically increase. Here, the frequency F1 is
This is the frequency at which the first voltage amplitude | V | becomes larger than the value determined by the inverter input voltage Vdc.

In the region where the induction motor speed fr is equal to or lower than the frequency F1, the first voltage amplitude | V | and the second voltage amplitude | V | fix
Are equal, the voltage deviation ΔV becomes zero, and the magnetic flux correction value ΔΦ also becomes zero.

Next, when the induction motor rotation speed fr becomes higher than the frequency F1, the first magnetic flux command Φref1 decreases as set in the table 51. As a result, the torque current command
IqRef increases, and the magnetic flux component current command IdRef decreases. The rate of increase of the d-axis voltage command VdRef, the q-axis voltage command VqRef, and the first voltage amplitude | V | also decreases.

However, despite the fact that the first magnetic flux command Φref1 is reduced by setting in the table 51, the first voltage amplitude | V | becomes larger than the value determined by the inverter input voltage Vdc, and the first voltage amplitude | V | | V | and the second voltage amplitude | V |
When the fix has a different value, the voltage deviation ΔV has a negative value. Then, the magnetic flux correction value calculator 59 calculates a magnetic flux correction value ΔΦ that makes the first voltage amplitude | V | equal to the second voltage amplitude | V | fix. As a result, the first magnetic flux command ΦRe
Even when the table 51 for changing f1 is not set optimally, the second secondary magnetic flux command ΦRef2 is calculated so as to maintain the vector control state, and the output voltage is fixed. , Vector control can be realized.

FIG. 10 is a timing chart showing the operation of the conventional vector control device in the fixed voltage region.

[0016]

The conventional vector control method in the fixed voltage region has the above configuration and operation. In this method, the vector control can be performed in the fixed voltage region. Since the calculation of the narrowing-down amount is determined in a feedback manner, not only an error due to a calculation delay may occur, but also it is difficult to adjust the constant depending on the configuration of the magnetic flux correction value calculation unit. It is hard to say that the vector control method is sufficient in the area.

The present invention has been made to solve the above-described problems, and realizes vector control not only in the variable voltage region but also in the fixed voltage region. It is an object of the present invention to provide a vector control device and method that do not require constant adjustment.

[0018]

According to a first aspect of the present invention, there is provided a vector control apparatus for performing vector control of an induction motor based on a torque command value, a first secondary magnetic flux command value, and an induction motor constant. Calculating a second secondary magnetic flux command value based on the torque command value, the first secondary magnetic flux command value, the inverter angular frequency, the induction motor constant, and the inverter input voltage set value. A second magnetic flux command calculation unit; and a vector control calculation unit that performs vector control using the second secondary magnetic flux command value and the torque command value.

According to a second aspect of the present invention, there is provided a vector control device for an induction motor for performing vector control of an induction motor based on a torque command value, a first secondary magnetic flux command value, and an induction motor constant. A secondary magnetic flux command calculator for calculating a second secondary magnetic flux command value based on the torque command value, the first secondary magnetic flux command value, an inverter angular frequency, the induction motor constant, and an inverter input voltage set value; A command switching unit that switches and sets either the first secondary magnetic flux command value or the second secondary magnetic flux command value according to an inverter angular frequency as a third secondary magnetic flux command value used for vector control; , A vector control operation unit that performs vector control using the third secondary magnetic flux command value and the torque command value.

According to a third aspect of the present invention, there is provided a vector control apparatus for an induction motor that performs vector control of an induction motor based on a torque command value, a first secondary magnetic flux command value, and an induction motor constant. A secondary magnetic flux command calculator for calculating a second secondary magnetic flux command value based on the torque command value, the first secondary magnetic flux command value, an inverter angular frequency, the induction motor constant, and an inverter input voltage set value; The third secondary magnetic flux command value used for vector control is switched and set by a voltage value calculated based on either the first secondary magnetic flux command value or the second secondary magnetic flux command value. A command switching unit; and a vector control operation unit that performs vector control using the third secondary magnetic flux command value and the torque command value.

According to a fourth aspect of the present invention, there is provided a vector control apparatus for an induction motor that performs vector control of an induction motor based on a torque command value, a first secondary magnetic flux command value, and an induction motor constant. A secondary magnetic flux command calculator for calculating a second secondary magnetic flux command value based on the torque command value, the first secondary magnetic flux command value, an inverter angular frequency, the induction motor constant, and an inverter input voltage set value; The first secondary magnetic flux command value and the second secondary magnetic flux command value as third secondary magnetic flux command values used for vector control.
A low-order selection unit that compares the secondary magnetic flux command values and sets a smaller one of them, and a vector control calculation unit that performs vector control using the third secondary magnetic flux command value and the torque command value It is.

According to a fifth aspect of the present invention, in the vector control apparatus for an induction motor according to any one of the first to fourth aspects, the secondary magnetic flux command calculating section includes:
The second secondary magnetic flux command value is calculated using the equations (1) to (7).

According to a sixth aspect of the present invention, there is provided a vector control apparatus for an induction motor according to any one of the first to fifth aspects, wherein the inverter angular frequency is corrected by the inverter input voltage value. Is further provided.

A vector control device according to a seventh aspect of the present invention is the vector control device for an induction motor according to any one of the first to sixth aspects, based on a deviation between a magnetic flux component current command and a magnetic flux component current of the induction motor. A compensating unit for calculating a compensation value ΔΦ, and as the fourth secondary magnetic flux command value used for vector control, the second secondary magnetic flux command value or the third secondary magnetic flux command value and the compensation value Δφ And an adder for setting a value obtained by the addition.

According to an eighth aspect of the present invention, in the vector control apparatus for an induction motor according to any one of the first to seventh aspects, the second secondary magnetic flux command value and the third The apparatus further includes a limiter for limiting an output value of the magnetic flux command value or the fourth secondary magnetic flux command value.

According to a ninth aspect of the present invention, there is provided a vector control method for an induction motor for performing vector control of an induction motor based on a torque command value, a first secondary magnetic flux command value, and an induction motor constant. Calculating a second secondary magnetic flux command value based on the torque command value, the first secondary magnetic flux command value, an inverter angular frequency, the induction motor constant, and an inverter input voltage set value;
Performing a vector control using the second secondary magnetic flux command value and the torque command value.

According to a tenth aspect of the present invention, there is provided a vector control method for an induction motor for performing vector control of an induction motor based on a torque command value, a first secondary magnetic flux command value, and an induction motor constant. Calculating a second secondary magnetic flux command value based on the torque command value, the first secondary magnetic flux command value, an inverter angular frequency, the induction motor constant, and an inverter input voltage set value;
Switching between the secondary magnetic flux command value and the second secondary magnetic flux command value according to the inverter angular frequency as a third secondary magnetic flux command value used for vector control, and setting a third secondary magnetic flux command value; And performing a vector control using the next magnetic flux command value and the torque command value.

A vector control apparatus according to an eleventh aspect of the present invention is a vector control method for an induction motor that performs vector control of an induction motor based on a torque command value, a first secondary magnetic flux command value, and an induction motor constant. Calculating a second secondary magnetic flux command value based on the torque command value, the first secondary magnetic flux command value, an inverter angular frequency, the induction motor constant, and an inverter input voltage set value;
A step of switching and setting the third secondary magnetic flux command value used in the vector control by a voltage value calculated based on either the first secondary magnetic flux command value or the second secondary magnetic flux command value; And a step of performing vector control using the third secondary magnetic flux command value and the torque command value.

According to a twelfth aspect of the present invention, there is provided a vector control method for an induction motor for performing vector control of an induction motor based on a torque command value, a first secondary magnetic flux command value, and an induction motor constant. Calculating a second secondary magnetic flux command value based on the torque command value, the first secondary magnetic flux command value, an inverter angular frequency, the induction motor constant, and an inverter input voltage set value;
Comparing the first secondary magnetic flux command value and the second secondary magnetic flux command value as a third secondary magnetic flux command value used for vector control, and setting a smaller value thereof; 3) performing vector control using the secondary magnetic flux command value and the torque command value.

A vector control device according to a thirteenth aspect of the present invention is the vector control method for an induction motor according to any one of the ninth to twelfth aspects, wherein the second secondary magnetic flux command value is (1) to ( 7) It is calculated using the equation.

According to a fourteenth aspect of the present invention, in the vector control method for an induction motor according to any one of the ninth to thirteenth aspects, a step of correcting the inverter angular frequency with the inverter input voltage value is provided. Further provisions are made.

A vector control device according to a fifteenth aspect of the present invention is the vector control method for an induction motor according to any one of the ninth to fourteenth aspects, wherein the vector control method is based on a deviation between a magnetic flux component current command and a magnetic flux component current of the induction motor. Calculating the compensation value ΔΦ by using the second secondary flux command value or the third secondary flux command value and the compensation value Δφ as a fourth secondary flux command value used for vector control. Setting a value obtained by the addition.

According to a sixteenth aspect of the present invention, in the vector control method for an induction motor according to any one of the ninth to fifteenth aspects, the second secondary magnetic flux command value;
The method further includes a step of limiting an output value of the third secondary magnetic flux command value or the fourth secondary magnetic flux command value.

[0034]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

Embodiment 1 FIG. 1 is a block diagram showing an apparatus for implementing a vector control method according to Embodiment 1 of the present invention. In FIG. 1, 1 is a torque command value T
* Secondary magnetic flux command value Φ2 *, Inverter angular frequency ωin
v, a secondary magnetic flux command calculation unit that calculates a second secondary magnetic flux command value Φ2 * 2 from the inverter input voltage reference value Vk and the induction motor constant of the induction motor 3 to be controlled.

Reference numeral 2 denotes a vector control operation unit for performing an operation for controlling the induction motor 3 based on the torque command value T * and the second secondary magnetic flux command value Φ2 * 2. Reference numeral 3 denotes an induction motor. Although only one induction motor 3 is shown in FIG. 1, the same applies to a state where n induction motors are connected in parallel.

Next, the operation of the vector control device according to the first embodiment will be described.

From the torque command value T *, the secondary magnetic flux command value Φ2 *, and the inverter angular frequency ωinv, the q-axis voltage command value e1q and the d-axis voltage command value e1d in the steady state in which the vector control is established are as follows: It can be obtained by using equations (1) to (3). The method of deriving this equation is described in, for example, "Vector Control of AC Motor" by Takayoshi Nakano, published by Nikkan Kogyo Shimbun, and is generally well known, and therefore will not be described here.

[0039]

[Equation 11] Here, the value obtained by squaring and adding the q-axis voltage command value e1q and the d-axis voltage command value e1d is defined as V.
It is expressed by equation (4).

[0040]

(Equation 12) Next, assuming that the input voltage set value of the inverter that supplies the voltage to the induction motor 3 is Vk, and the voltage at which the output voltage of the inverter becomes maximum is Vmax, Vmax can be expressed by equation (5).

[0041]

(Equation 13) Then, the voltage V obtained by the above equation (4) and the voltage V obtained by the above (5)
Compare the voltage Vmax obtained by the formula and calculate the smaller value as V2
And

V2 = VV <Vmax V2 = Vmax V ≧ Vmax Next, in the above equation (4), when φ is obtained by replacing φ = Φ2 * ² and V2 = V, the following equation (6) is obtained. .

[0043]

[Equation 14] That is, the second secondary magnetic flux command value Φ2 * 2 is

(Equation 15) Can be obtained by

In the secondary magnetic flux command correction unit 1, the above (1) to
The calculation of (7) is performed to calculate the second secondary magnetic flux command value Φ2 * 2, the second secondary magnetic flux command value Φ2 * 2 is output to the vector control calculation unit 2, and the vector control calculation unit 2 controls the induction motor 3 based on the torque command value T * and the second secondary magnetic flux command value Φ2 * 2.

FIG. 2 shows a timing chart of the vector control device according to the first embodiment. In the timing chart of FIG. 2, for comparison with FIG. 10 shown as a conventional example, the magnetic flux component current command value IdRef and the torque component current command value IqRef, d which are internal signals of the vector control operation unit 2 in FIG. Shaft voltage command value VdRef, q-axis voltage command value VqRe
f, voltage amplitude | V |, and inverter input voltage Vdc are shown.

As described above, according to the vector control device shown in FIG. 1, the secondary magnetic flux command calculation unit performs the calculations of the equations (1) to (7) to include the operation region where the voltage is fixed. In all operating regions, the optimum secondary magnetic flux command value is calculated in a feed-forward manner. Therefore, as shown in the conventional example, the control delay generated for calculating the magnetic flux command value in a feedback manner and the controller Is unnecessary, and stable vector control can be realized in the entire operation range.

Embodiment 2 FIG. 3 shows the configuration of an apparatus for performing vector control according to Embodiment 2 of the present invention. In the vector control device according to the first embodiment shown in FIG. 1 described above, the second secondary magnetic flux command value Φ2 * 2 calculated by the secondary magnetic flux command calculation unit 1 is input to the vector control calculation unit. In the vector control device shown in FIG. 3, the third secondary magnetic flux command value Φ2 * 3 input to the vector control operation unit is changed to the secondary magnetic flux command value Φ2 by the inverter angular frequency.
2 * or the second secondary magnetic flux command value Φ2 * 2 is set.

In FIG. 3, reference numeral 4 denotes a switching signal cs which receives the inverter angular frequency and the switching frequency ωst as inputs.
Command switching unit for outputting f, 5 is a secondary magnetic flux command value Φ2
A selection switch for selecting either * or the second secondary magnetic flux command value Φ2 * 2 based on a switching signal csf from the command switching unit 4. The other configuration of the vector control device shown in FIG. 3 is the same as the configuration of the vector control device shown in FIG.

Next, the operation of the vector control apparatus according to the second embodiment shown in FIG. 3 will be described focusing on the differences from the first embodiment. The command switching unit 4 based on the frequency includes an inverter angular frequency ωinv and a switching frequency set value ωst
When the inverter angular frequency ωinv is smaller than the switching frequency set value ωst, the switching signal csf is set to L,
The inverter angular frequency ωinv is the switching frequency set value ωs
When it becomes larger than t, the switching signal csf becomes high level (H).
To

The selection switch 5 receives the switching signal csf from the command switching unit 4 based on the frequency. When the switching signal csf is at a low level (L), the third secondary magnetic flux command Φ2
* 3 is set to the secondary magnetic flux command Φ2 *, and the switching signal csf
Is H, the third secondary magnetic flux command Φ2 * 3 is set to the second secondary magnetic flux command Φ2 * 2.

The other operations of the vector control device shown in FIG. 3 are the same as those of the vector control device shown in FIG. 1. In the vector control device shown in FIG. The command value Φ2 * 3 can be arbitrarily set to the second secondary magnetic flux command value Φ2 * 2 or the secondary magnetic flux command value Φ2 * obtained by the secondary magnetic flux command calculation unit 1 by the inverter angular frequency ωinv. When the calculations of equations (1) to (7) performed by the next magnetic flux command calculation unit 1 are performed by a microcomputer or the like, the calculation does not need to be performed in a region equal to or lower than the inverter angular frequency ωinv. There is an advantage that the burden such as can be reduced.

Embodiment 3 FIG. FIG. 4 shows a configuration of an apparatus for implementing the vector control method according to the third embodiment of the present invention. In the vector control device according to the second embodiment shown in FIG. 3 described above, the third magnetic flux command value Φ2 * 3 input to the vector control calculation unit is converted by the secondary magnetic flux command calculation unit 1 by the inverter angular frequency. Although the calculated second secondary magnetic flux command value Φ2 * 2 or the secondary magnetic flux command value Φ2 * has been switched, the vector control device shown in FIG. Command value Φ2
* 3 is set to the secondary magnetic flux command value Φ2 * or the second secondary magnetic flux command Φ2 * 2 by the voltage V calculated by the equation (4).

In FIG. 4, reference numeral 6 denotes a secondary magnetic flux command calculation unit 1
The command switching unit 7 receives the voltage V and the switching voltage Vst calculated in the above as inputs and outputs a switching signal csv. 7 is a secondary magnetic flux command value Φ2 * and a second secondary magnetic flux command value Φ2 * 2.
The switching signal cs from the command switching unit 6
This is a selection switch selected by v. The other configuration of the vector control device shown in FIG. 4 is the same as the configuration of the vector control device shown in FIG.

Next, the operation of the vector control device according to the third embodiment shown in FIG. 4 will be described, focusing on the differences from the first embodiment. The command switching unit 6 compares the voltage V calculated by the equation (4) with the switching voltage set value Vst in the secondary magnetic flux command calculating unit 1, and when the voltage V is smaller than the switching voltage set value Vst, the switching signal Let csv be L,
When the voltage V exceeds the switching voltage set value Vst, the switching signal csv is set to H.

The selection switch 7 receives a switching signal csv from the command switching unit 6 based on a voltage. When the switching signal csv is L, the third secondary magnetic flux command value Φ2 * 3 is changed to the secondary magnetic flux command value Φ2 *. And when the switching signal csv is H, the third secondary magnetic flux command value Φ2 * 3 is set to the second secondary magnetic flux command value Φ2 * 2.

The other operations of the vector control device shown in FIG. 4 are the same as those of the vector control device shown in FIG. 1. In the vector control device shown in FIG. Command value Φ2 * 3 is converted to secondary magnetic flux calculation unit 1
The second secondary magnetic flux command Φ2 * obtained by the secondary magnetic flux command calculation unit 1 by the voltage V calculated by the equation (4)
Since the secondary magnetic flux command value Φ2 * can be arbitrarily set, for example, when the calculations of the equations (1) to (7) performed by the secondary magnetic flux command calculation unit 1 are performed by a microcomputer or the like, In a region where the voltage V calculated by the expression 4) is smaller than the switching voltage set value Vst, the calculations of the expressions (5) to (7) do not need to be performed, and the advantage that the load on the microcomputer or the like can be reduced is obtained. is there.

Embodiment 4 FIG. FIG. 5 shows the configuration of an apparatus for implementing the vector control method according to the fourth embodiment of the present invention. In the vector control device shown in FIGS. 3 and 4, the third magnetic flux command value Φ2 * 3 input to the vector control calculation unit 2 is obtained by the secondary magnetic flux command calculation unit 1 based on the inverter angular frequency or voltage. Although the second secondary magnetic flux command value Φ2 * 2 or the secondary magnetic flux command value Φ2 * is switched to the second secondary magnetic flux command value Φ2 * 2 in the vector control device of the fourth embodiment shown in FIG. 2
The secondary magnetic flux command value Φ2 * 3 is set to a smaller value between the second secondary magnetic flux command Φ2 * 2 and the secondary magnetic flux command value Φ2 *.

In FIG. 5, reference numeral 8 denotes a secondary magnetic flux command value Φ2 *.
And the second secondary magnetic flux command Φ2 * 2 as input,
This is a low-order selection unit that outputs the next magnetic flux command value Φ2 * 3. Other configurations of the vector control device shown in FIG. 5 are the same as those of the vector control device shown in FIG.

Next, the operation of the vector control device according to the fourth embodiment shown in FIG. 5 will be described focusing on the differences from the first embodiment. The low-order selector 8 is configured to output the secondary magnetic flux command value Φ2 *
Is compared with the second secondary magnetic flux command value Φ2 * 2, and a smaller one of them is set as a third secondary magnetic flux command value Φ2 * 3, and is output to the vector control calculation unit 2. The vector control calculation unit 2 controls the induction motor 3 using the third secondary magnetic flux command value Φ2 * 3 and the torque command value T *.

Other operations of the vector control device shown in FIG. 5 are the same as those of the vector control device shown in FIG. 1. In the vector control device shown in FIG. Since a small value among the second secondary magnetic flux command values Φ2 * 2 can be set as the third secondary magnetic flux command value Φ2 * 3, the second secondary magnetic flux command value Φ2 * 2 is calculated by the equations (1) to (7) due to a calculation error or the like. Even when the second secondary magnetic flux command value Φ2 * 2 becomes larger than the secondary magnetic flux command value Φ2 *, the vector control state can be maintained.

Embodiment 5 FIG. 6 shows a configuration of an apparatus for implementing a vector control method according to Embodiment 5 of the present invention. In the above-described vector control devices of FIGS. 1 and 3 to 5, the inverter angular frequency ωinv input to the secondary magnetic flux command calculation unit 1 is the same as the frequency for controlling the induction motor 3. In the illustrated vector control device, the inverter angular frequency input to the secondary magnetic flux command calculation unit 1 is set to a value corrected by the inverter input voltage.

In FIG. 6, reference numeral 9 denotes an inverter angular frequency ω.
A multiplier that multiplies inv by the correction coefficient Kω and outputs a second inverter angular frequency ωinv2, and a divider 10 divides the inverter input voltage reference value Vk by the inverter input voltage Vin and outputs a correction coefficient Kω. . Other configurations of the vector control device shown in FIG. 6 are the same as those of the vector control device shown in FIGS. 1 and 3 to 5, and the functions of the vector control device shown in FIG. Can be applied to the vector control device shown in FIG. Note that the multiplier 9 and the divider 10 constitute correction means for correcting the inverter angular frequency with the inverter input voltage value.

Next, the operation of the vector control device according to the fifth embodiment shown in FIG. 6 will be described. By the divider 10,
The ratio of the inverter input voltage Vin during the vector control operation to the inverter input voltage reference value Vk is calculated, and a multiplier 9
As the correction coefficient Kω. The multiplier 9 multiplies the inverter angular frequency ωinv by the correction coefficient Kω, and outputs the result of the multiplication to the secondary magnetic flux command calculation unit 1 using the second inverter angular frequency ωin.
Output as inv2. The secondary magnetic flux command calculator 1 converts the inverter angular frequency ωinv to the second inverter angular frequency ωi
In place of nv2, the calculations of equations (1) to (7) are performed to calculate the second secondary magnetic flux command value Φ2 * 2.

In the vector control device shown in FIG. 6, the secondary magnetic flux command calculating section 1 calculates the second secondary magnetic flux command value Φ2 * 2 in consideration of the inverter input voltage.
When the inverter input voltage becomes larger than the inverter input voltage reference value Vk, the inverter angular frequency ωinv
The second inverter angular frequency ωinv2 is reduced to calculate a secondary magnetic flux command value. When the inverter input voltage becomes smaller than the inverter input voltage reference value Vk, the inverter angular frequency ωinv is Since the secondary magnetic flux command value can be calculated by increasing the second inverter angular frequency ωinv2, even when the inverter input voltage is different from the inverter input voltage reference value Vk, the optimum second secondary magnetic flux command value is obtained. By calculating Φ2 * 2, vector control can be performed.

Embodiment 6 FIG. FIG. 7 shows a configuration of an apparatus for implementing a vector control method according to Embodiment 6 of the present invention. In the vector control device shown in FIG. 1 and FIGS.
The second secondary magnetic flux command value Φ2 * 2 or the third secondary magnetic flux command value Φ2 * 3 is input to the vector control operation unit 3 to control the induction motor 3, but the vector shown in FIG. In the control device, a compensation value ΔΦ is calculated by a compensating unit by using a deviation of a magnetic flux component current command value and a magnetic flux component current used for vector control as inputs, and the compensation value ΔΦ and a second magnetic flux command value Φ2 *
A value obtained by adding the second or third secondary magnetic flux command value Φ2 * 3 is input to the vector control operation unit.

In FIG. 7, reference numeral 11 denotes a magnetic flux component current command value ID.
A subtractor 12 subtracts the magnetic flux component current IDF from R and outputs a magnetic flux component current deviation DIDR. The subtractor 12 receives the magnetic flux component current deviation DIDR as an input, and acts to make the magnetic flux component current deviation zero, thereby forming a compensation value ΔΦ. The compensator 13 for outputting the second magnetic flux command value Φ2 *
2nd or 3rd secondary magnetic flux command value Φ2 * 3 and compensation value ΔΦ
And outputs a fourth secondary magnetic flux command value Φ2 * 4 to the vector control calculation unit 2. Other configurations of the vector control device shown in FIG. 7 are the same as those of the vector control device shown in FIGS. 1 and 3 to 6, and the functions of the vector control device shown in FIG. Can be applied to the vector control device shown in FIG.

Next, the operation of the vector control device according to the sixth embodiment will be described. The subtractor 11 subtracts the magnetic flux component current IDF from the magnetic flux component current command value IDR used for vector control, obtains a magnetic flux component current deviation DIDR, and outputs the deviation to the compensator 12. The compensator 12 calculates a compensation value ΔΦ that adjusts the magnetic flux current deviation DIDR to zero, and outputs it to the adder 13. In the adder 13, the compensation value ΔΦ and the second secondary magnetic flux command value Φ2 in FIG.
The fourth magnetic flux command value Φ2 * 4 is calculated by adding the secondary magnetic flux command value Φ2 * 3 to the vector control calculation unit 2. The vector control calculation unit 2 controls the induction motor 3 based on the fourth secondary magnetic flux command value Φ2 * 4.

The vector control device shown in FIG. 7 calculates a compensation value ΔΦ to adjust the magnetic flux component current deviation IDR to zero, and corrects the secondary magnetic flux command value used in the vector control calculation unit 1 to obtain an induction value. Due to motor constant error, etc.
Even when the second secondary magnetic flux command value Φ2 * 2 calculated by the equations (1) to (7) includes an error, the vector control can be realized.

Embodiment 7 FIG. 8 shows the configuration of an apparatus for implementing the vector control method according to the seventh embodiment of the present invention. In the vector control device of FIG. 1 and FIGS.
Although the second secondary magnetic flux command value Φ2 * 2, the third secondary magnetic flux command value Φ2 * 3, or the fourth secondary magnetic flux command value Φ2 * 4 is input to the vector control calculation unit 2, , FIG.
The second secondary magnetic flux command value Φ2 *
2, the third secondary magnetic flux command value Φ2 * 3, or the fourth
A limiter for limiting the magnitude of the secondary magnetic flux command value Φ2 * 4 is provided, and a fifth secondary magnetic flux command value Φ limited by the limiter is provided.
2 * 5 is output to the vector control operation unit 2.

In FIG. 8, reference numeral 14 designates the second secondary magnetic flux command value Φ2 * 2, the third secondary magnetic flux command value Φ2 * 3, or the fourth secondary magnetic flux command value Φ2 * 4. , Fifth 2
It is a limiter that outputs the next magnetic flux command value Φ2 * 5. The functions of the vector control device shown in FIG.
7 can be applied to the vector control devices shown in FIGS.

Next, the operation of the seventh embodiment will be described. The limiter 14 has a second secondary magnetic flux command value Φ2
* 2, a third secondary magnetic flux command value Φ2 * 3, or a fourth secondary magnetic flux command value Φ2 * 4. In the limiter 14, a maximum value Φmax and a minimum value Φmin of the secondary magnetic flux command value used in the vector control calculation unit 2 are set.

The limiter 14 determines whether the input second secondary magnetic flux command value Φ2 * 2, third secondary magnetic flux command value Φ2 * 3, or fourth secondary magnetic flux command value Φ2 * 4 is the secondary magnetic flux command value. When it is larger than the command maximum value Φmax, the fifth secondary magnetic flux command value Φ2
The secondary magnetic flux command maximum value Φmax is output as * 5.

The limiter 14 receives the second commanded secondary magnetic flux Φ2 * 2 and the third commanded secondary magnetic flux Φ2 *
When the third or fourth secondary magnetic flux command value Φ2 * 4 is smaller than the secondary magnetic flux command minimum value Φmin, the secondary magnetic flux command minimum value Φmin is output as the fifth secondary magnetic flux command value Φ2 * 5.

The input second secondary magnetic flux command value Φ
2 * 2, third secondary magnetic flux command value Φ2 * 3, or fourth
Is the secondary magnetic flux command maximum value Φmax
When it is smaller and larger than the minimum secondary magnetic flux command value Φmin, the second secondary magnetic flux command value Φ2 * 2 and the third secondary magnetic flux command value that are input as the fifth secondary magnetic flux command value Φ2 * 5 Needless to say, Φ2 * 3 or the fourth secondary magnetic flux command value Φ2 * 4 is output as it is.

In the vector control device shown in FIG. 8, the fifth secondary magnetic flux command value Φ2 * 5
Is limited, the second secondary magnetic flux command value Φ2 *
2, the third secondary magnetic flux command value Φ2 * 3, or the fourth
It is possible to avoid that the next magnetic flux command value Φ2 * 4 becomes a negative value due to, for example, a calculation error or the like, or a magnetic flux set value that clearly saturates the induction motor 3.

[0076]

According to the vector control apparatus and method for an induction motor, vector control is realized not only in the variable voltage region but also in the fixed voltage region, there is no calculation delay, and there is no need to adjust constants of the controller and the like. There is an effect that necessary vector control can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a vector control device according to a first embodiment of the present invention.

FIG. 2 is a timing chart showing an operation of the vector control device according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a vector control device according to a second embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a vector control device according to a third embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a vector control device according to a fourth embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a vector control device according to a fifth embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a vector control device according to a sixth embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of a vector control device according to a seventh embodiment of the present invention.

FIG. 9 is a block diagram showing a configuration of a conventional vector control device.

FIG. 10 is a timing chart showing the operation of a conventional vector control device.

[Explanation of symbols]

1 Secondary magnetic flux command calculation unit, 2 Vector control calculation unit, 3
Induction motor, 4 command switching unit, 5 selection switch, 6 command switching unit, 7 selection switch, 8 low order selection unit, 9 multiplier, 10 divider, 11 subtractor, 12
Compensator, 13 adder, 14 limiter, 51 table, 52 first adder, 53 vector control calculator,
54 voltage FF calculation unit, 55 polar coordinate conversion unit, 56 voltage fixed unit, 57 PWM calculation unit, 58 first subtractor, 59
Magnetic flux correction value calculation unit, 60 second adder, 61 integrator, 62 third adder. 63 coordinate conversion unit, 64 second subtractor, 65 secondary resistance correction unit.

Claims (16)

[Claims] 1. An induction motor vector control device that performs vector control of an induction motor based on a torque command value, a first secondary magnetic flux command value, and an induction motor constant, wherein the torque command value, the first 2 A secondary magnetic flux command calculator for calculating a second secondary magnetic flux command value based on a secondary magnetic flux command value, an inverter angular frequency, the induction motor constant, and an inverter input voltage set value; and the second secondary magnetic flux command value A vector control device for an induction motor, comprising: a vector control operation unit that performs vector control using a torque command value. 2. A vector control device for an induction motor that performs vector control of an induction motor based on a torque command value, a first secondary magnetic flux command value, and an induction motor constant, wherein the torque command value, the first 2 A secondary magnetic flux command calculator for calculating a second secondary magnetic flux command value based on a secondary magnetic flux command value, an inverter angular frequency, the induction motor constant, and an inverter input voltage set value; and a third secondary used for vector control. A command switching unit that sets either the first secondary magnetic flux command value or the second secondary magnetic flux command value as a magnetic flux command value by changing an inverter angular frequency; and the third secondary magnetic flux command value. A vector control device for an induction motor, comprising: a vector control operation unit that performs vector control using the torque command value. 3. An induction motor vector control device for performing vector control of an induction motor based on a torque command value, a first secondary magnetic flux command value, and an induction motor constant, wherein the torque command value, the first 2 A secondary magnetic flux command calculator for calculating a second secondary magnetic flux command value based on a secondary magnetic flux command value, an inverter angular frequency, the induction motor constant, and an inverter input voltage set value; and a third secondary used for vector control. A command switching unit configured to switch and set as a magnetic flux command value by a voltage value calculated based on either the first secondary magnetic flux command value or the second secondary magnetic flux command value; A vector control device for an induction motor, comprising: a vector control operation unit that performs vector control using a next magnetic flux command value and the torque command value. 4. An induction motor vector control device for performing vector control of an induction motor based on a torque command value, a first secondary magnetic flux command value, and an induction motor constant, wherein the torque command value, the first 2 A secondary magnetic flux command calculator for calculating a second secondary magnetic flux command value based on a secondary magnetic flux command value, an inverter angular frequency, the induction motor constant, and an inverter input voltage set value; and a third secondary used for vector control. As a magnetic flux command value, the first secondary magnetic flux command value and the second secondary magnetic flux command value are compared, and a low-order selecting unit that sets a smaller value among them, and the third secondary magnetic flux command value and And a vector control operation unit that performs vector control using the torque command value. 5. The vector control device for an induction motor according to claim 1, wherein the secondary magnetic flux command calculation unit is configured to calculate the following equation (1) to (7). (Equation 2) (Equation 3) (Equation 4) (Equation 5) The vector control device for an induction motor, wherein the second secondary magnetic flux command value is calculated using the following. 6. The induction motor vector control device according to claim 1, further comprising a correction unit that corrects the inverter angular frequency with the inverter input voltage value. Vector control device. 7. The vector control device for an induction motor according to claim 1, wherein a compensation unit that calculates a compensation value ΔΦ based on a deviation between a magnetic flux current command and a magnetic flux current of the induction motor. An adder for setting a value obtained by adding the second secondary magnetic flux limit value or the third secondary magnetic flux command value and the compensation value Δφ as a fourth secondary magnetic flux command value used for vector control. A vector control device for an induction motor, further comprising: 8. The vector control device for an induction motor according to claim 1, wherein the second secondary magnetic flux command value, the third secondary magnetic flux command value, or the fourth secondary magnetic flux command value. A vector control device for an induction motor, further comprising a limiter for limiting an output value of a magnetic flux command value. 9. A vector control method for an induction motor that performs vector control of an induction motor based on a torque command value, a first secondary magnetic flux command value, and an induction motor constant, wherein the torque command value, the first 2 Calculating a second secondary magnetic flux command value based on a secondary magnetic flux command value, an inverter angular frequency, the induction motor constant, and an inverter input voltage set value; and the second secondary magnetic flux command value and the torque command value. Performing a vector control using: a vector control method for an induction motor. 10. A vector control method for an induction motor that performs vector control of an induction motor based on a torque command value, a first secondary magnetic flux command value, and an induction motor constant, wherein the torque command value, the first 2 Calculating a second secondary magnetic flux command value based on a secondary magnetic flux command value, an inverter angular frequency, the induction motor constant, and an inverter input voltage set value; and as a third secondary magnetic flux command value used for vector control, A step of switching and setting either the secondary magnetic flux command value or the second secondary magnetic flux command value by the inverter angular frequency; and a vector control using a third secondary magnetic flux command value and the torque command value. And a vector control method for an induction motor. 11. An induction motor vector control method for performing vector control of an induction motor based on a torque command value, a first secondary magnetic flux command value, and an induction motor constant, wherein the torque command value, the first 2 Calculating a second secondary magnetic flux command value based on a secondary magnetic flux command value, an inverter angular frequency, the induction motor constant, and an inverter input voltage set value; and as a third secondary magnetic flux command value used for vector control, Switching and setting by a voltage value calculated based on either the first secondary magnetic flux command value or the second secondary magnetic flux command value; and the third secondary magnetic flux command value and the torque. Performing a vector control using a command value. A vector control method for an induction motor, comprising: 12. A vector control method for an induction motor for performing vector control of an induction motor based on a torque command value, a first secondary magnetic flux command value, and an induction motor constant, wherein the torque command value, the first 2 Calculating a second secondary magnetic flux command value based on a secondary magnetic flux command value, an inverter angular frequency, the induction motor constant, and an inverter input voltage set value; and as a third secondary magnetic flux command value used for vector control, Comparing the first secondary magnetic flux command value and the second secondary magnetic flux command value, and setting a smaller value of the first secondary magnetic flux command value; and setting the third secondary magnetic flux command value and the torque command value Performing a vector control using: a vector control method for an induction motor. 13. The vector control method for an induction motor according to claim 9, wherein the second secondary magnetic flux command value is given by the following formulas (1) to (7). (Equation 7) (Equation 8) (Equation 9) (Equation 10) A vector control method for an induction motor, wherein the vector control is performed using 14. The vector control method for an induction motor according to claim 9, further comprising a step of correcting the inverter angular frequency with the inverter input voltage value. Vector control method. 15. The vector control method for an induction motor according to claim 9, wherein a compensation value ΔΦ is calculated based on a deviation between a magnetic flux component current command and a magnetic flux component current of the induction motor. A step of setting, as a fourth secondary magnetic flux command value used for vector control, a value obtained by adding the second secondary magnetic flux command value or the third secondary magnetic flux command value and the compensation value Δφ A vector control method for an induction motor, further comprising: 16. The vector control method for an induction motor according to claim 9, wherein the second secondary magnetic flux command value, the third secondary magnetic flux command value, or the fourth secondary magnetic flux command value. A vector control method for an induction motor, further comprising a step of limiting an output value of a magnetic flux command value.