JPH0549285A - Vector control processor for induction motor - Google Patents

Abstract

PURPOSE:To suppress hunting of an induction motor due to fluctuation of exciting component current by fixing the exciting component current to be fed to the induction motor under positioning stop control mode. CONSTITUTION:Upon decision of position control loop, a comparator section makes a decision whether a position difference is lower than a predetermined level based on a signal fed from a position control amplifier 28. A torque component current command igs is fed, as it is, to a secondary flux weakening circuit 20 from a limiter circuit 10 before the position difference drops below the predetermined level. When the comparator section detects a position difference lower than a predetermined value even once, multiplying coefficient of secondary flux phi is fixed at a predetermined value. Consequently, the second flux phi2 is settled in the vicinity of a target stop position and micro vibration or hunting of an induction motor due to fluctuation of exciting component current caused by fluctuation of the secondary flux phi2 can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction motor vector control arithmetic unit, and more particularly to an induction motor vector control arithmetic unit capable of preventing minute vibration and hunting and performing positioning stop.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram showing a conventional vector control arithmetic unit (100) for an induction motor. (1)
Is a three-phase AC power supply, (2) is a converter circuit that converts three-phase AC into DC, (3) is a smoothing capacitor, and (4) is an inverter circuit that converts DC into three-phase AC.

Reference numeral (5) is an induction motor driven by an inverter circuit (4). (6) is a speed detector for detecting the speed of the induction motor (5). (21)
Is a position detector for detecting the position of the induction motor (5).

Reference numeral (29) is a position detection circuit for outputting a position detection signal pr corresponding to the output signal of the position detector (21). (27) is a target stop position command circuit that outputs a target stop position command signal ps. (28) is a position control amplifier that outputs a position control signal wp according to the deviation between the position detection signal pr and the stop position command signal pr.

(26) is a speed command signal ws for positioning.
This is a speed command circuit for positioning output.

(8) is a speed command circuit for outputting a speed command signal ωr *.

Reference numerals (22), (23) and (24) denote changeover switches.

(7) is a speed detection circuit for outputting a speed detection signal ωr corresponding to the output signal of the speed detector (6).

Reference numeral (25) is a positioning sequence circuit for controlling switching of the changeover switches (22), (23) and (24) based on the speed detection signal ωr.

(9) is a PI control circuit for performing proportional and integral control calculation of the difference between the speed command signal ωr * or the positioning speed command signal ws or the position control signal wp and the speed detection signal ωr. Reference numeral (10) is a limiter circuit that controls the output of the PI control circuit (9) at a predetermined saturation value and outputs the torque current command iqs *.

(11) is a secondary magnetic flux pattern generation circuit for generating an original secondary magnetic flux φ2 'from the speed detection signal ωr. Reference numeral (20) is a secondary magnetic flux weakening circuit that calculates k · φ2 ′ for the original secondary magnetic flux φ2 ′ and outputs the secondary magnetic flux φ2. As shown in FIG. 5, the constant k is set to <1.0> when the torque component current command iqs * is a predetermined value a or more, and is linear from <1.0> to <b> from the predetermined value a to “0”. Change to. The reason for providing the secondary magnetic flux weakening circuit (20) is as follows. That is, the induction motor (5) generates excitation noise and vibration in proportion to the secondary magnetic flux φ2. These exciting sounds and vibrations are not noticeable at high speeds, but are noticeable at low speeds. Therefore, when the speed is low, the secondary magnetic flux φ2 is weakened to reduce excitation noise and vibration. For this purpose, a secondary magnetic flux weakening circuit (20) is provided.

(12) is a first-order lag element for generating a secondary magnetic flux command φ2 * from the secondary magnetic flux φ2, (13) is a mutual reactance pattern generating circuit for generating a motor mutual reactance M from the secondary magnetic flux command φ2 *, ( 14) is the secondary magnetic flux φ
2 and the motor mutual reactance M, the excitation current command i
It is an excitation current calculation circuit that outputs ds *.

(15) is an amplitude calculation circuit for calculating the primary current amplitude | I1 | from the torque component current command iqs * and the excitation component current command ids *, and (16) is the torque component current command iq.
From s * and excitation current command ids *, primary current phase angle △
A phase angle calculation circuit that calculates θ, and (17) is a slip angular frequency calculation circuit that calculates the slip angular frequency ωs from the torque current command iqs * and the secondary magnetic flux command φ2 *.

(18) U given to the induction motor (5) from the primary current amplitude | I1 |, the primary current phase angle Δθ, and the angular velocity ωo which is the sum of the slip angular frequency ωs and the velocity detection signal ωr. It is a primary current reference generation circuit that generates a primary current command ius of the phase and a primary current command ivs of the V phase.

(19) is a U-phase primary current command ius,
Based on the V-phase primary current command ivs and the feedback signal If of the primary current I1 flowing through the induction motor (5), ON / OFF of the transistor of the inverter circuit (4) is controlled to 1
It is a current control circuit that controls the next current I1.

Next, referring to FIG. 6, the positioning stopping operation of the vector control arithmetic unit (100) of the induction motor will be described. Positioning sequence circuit (2
In 5), the changeover switch (22) is turned on, the changeover switch (23) is turned on, and the changeover switch (24) is turned off. At this time, the PI control circuit (9) performs proportional and integral control calculation of the difference between the speed command signal ωr * and the speed detection signal ωr.

When a positioning command is input to the positioning sequence circuit (25), the positioning sequence circuit (2
In 5), the changeover switch (22) is turned off, the changeover switch (23) is turned on, and the changeover switch (24) is turned off. At this time, the PI control circuit (9) performs proportional and integral control calculation of the difference between the positioning speed command signal ws and the speed detection signal ωr.

When the speed detection signal ωr reaches the positioning speed command signal ws, the positioning sequence circuit (25)
Turns off the changeover switch (22), turns off the changeover switch (23), and turns on the changeover switch (24). At this time, the PI control circuit (9) outputs the position control signal w
Proportional and integral control operations are performed on the difference between p and the speed detection signal ωr. That is, it becomes a position control loop, approaches the target stop position at a speed according to the position deviation between the current position and the target stop position, and stops.

[0019]

In the conventional vector control arithmetic unit (100) for an induction motor, the V-shaped secondary magnetic flux weakening circuit (20) is applied not only during the speed control loop but also during the position control loop. Characteristics work. Therefore, in the vicinity of the target stop position, the secondary magnetic flux φ2 is changed according to the position deviation.
Changes. Then, the excitation current command ids * also changes, and the excitation current changes. However, when the excitation control current changes corresponding to the position deviation when the position control loop is almost stopped near the target stop position, slight vibration and hunting are likely to occur due to slight position fluctuations. There is.

The present invention has been made in order to solve the above problems, and vector control calculation of an induction motor which prevents generation of microvibration or hunting when reaching the vicinity of a target stop position in a position control loop. The purpose is to obtain the device.

[0021]

A vector control arithmetic unit for an induction motor according to the present invention divides a primary current applied to the induction motor into a torque component current and an excitation component current, and determines the ratio of the excitation component current according to the size of a load. In a vector control arithmetic unit of an induction motor that performs control for changing, a positioning stop control mode detection means for detecting that the positioning stop control mode is in effect, and in the positioning stop control mode, the ratio of the excitation component current is fixed regardless of the size of the load. It is characterized in that an exciting current ratio fixing means is provided.

Further, the vector control arithmetic unit for an induction motor according to the present invention divides the primary current applied to the induction motor into a torque component current and an excitation component current, and performs control to change the ratio of the excitation component current depending on the size of the load. In the vector control arithmetic unit of the induction motor, a positioning stop control mode detecting means for detecting that it is in the positioning stop control mode, an arrival detecting means for detecting that the target stop position has been reached, and a positioning stop control mode Further, the present invention is characterized in that an exciting component current ratio fixing means is provided for fixing the ratio of the exciting component current regardless of the size of the load even after reaching the vicinity of the target stop position even once.

[0023]

In the vector control arithmetic unit for an induction motor according to the present invention, the excitation current component supplied to the induction motor is fixed during positioning stop control, so that minute vibration or hunting can be prevented.

[0024]

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

First Embodiment FIG. 1 is a block diagram showing a vector control arithmetic unit (51) for an induction motor according to a first embodiment of the present invention. This induction motor vector control arithmetic unit (51) has the same configuration as the induction motor vector control arithmetic unit (100) of FIG.
This is a configuration in which a torque component current command fixing circuit (40) is added.

The torque component current command fixing circuit (40) comprises a speed control loop / position control loop determination unit, a comparator unit and an output fixing unit.

The speed control loop / position control loop determination unit determines that the position control amplifier (28) is the speed control loop when no output is output, and the position control amplifier (28) is output the position control loop. To determine. When it is determined to be the speed control loop, the torque component current command fixing circuit (40)
Is a torque component current command iq from the limiter circuit (10).
Output s * as it is to the secondary magnetic flux weakening circuit (20).
Therefore, the operation in the speed control loop is the same as the conventional one. When it is determined to be the position control loop, the comparator unit determines whether or not the position deviation is equal to or less than a predetermined value based on the signal coming from the position control amplifier (28). That is,
It is determined whether the target stop position has been reached.

The output fixing unit receives the torque component current command iqs * from the limiter circuit (10) as it is before the secondary deviation weakening circuit ( 20). But,
When the comparator unit detects that the positional deviation is equal to or less than the predetermined value even once, the φ2 magnification coefficient k is fixed to the constant value d as shown in FIG. As a result, the secondary magnetic flux φ2 becomes constant in the vicinity of the target stop position, and it is prevented that the excitation current component fluctuates due to the change of the secondary magnetic flux φ2, and the induction motor (5) is not vibrated or hunted.

Embodiment 2 FIG. 3 is a block diagram showing a vector control arithmetic unit (11) for an induction motor according to the present invention. This induction motor vector control arithmetic unit (11) is a secondary magnetic flux weakening circuit (2) of the induction motor vector control arithmetic unit (100) of FIG.
0), a target stop position arrival detection part (41) and a secondary magnetic flux fixing part (42) are added. The target stop position arrival detection unit (41) detects that the target stop position is reached based on the output of the position control amplifier (28). The secondary magnetic flux fixing circuit (42) includes a target stop position arrival detection circuit (4
The secondary magnetic flux φ2 is fixed based on the detection signal of 1).

As a result, once the target stop position is reached, the secondary magnetic flux φ2 becomes constant, and the change of the secondary magnetic flux φ2 causes the excitation component current to fluctuate, causing slight vibration or hunting in the induction motor (5). To be prevented.

[0031]

As described above, according to the vector control arithmetic unit for an induction motor of the present invention, the excitation component current supplied to the induction motor is fixed in the positioning stop control mode. Micro vibration or hunting that occurs in the induction motor is suppressed.

[Brief description of drawings]

FIG. 1 is a block diagram of a vector control arithmetic unit for an induction motor according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram for fixing a ratio of exciting current.

FIG. 3 is a block diagram of a vector control arithmetic unit for an induction motor according to a second embodiment of the present invention.

FIG. 4 is a block diagram showing an example of a conventional vector control arithmetic device for an induction motor.

FIG. 5 is an explanatory diagram showing V characteristics.

FIG. 6 is an explanatory diagram showing a relationship between speed change and ON / OFF of a changeover switch during a positioning stop operation.

[Explanation of symbols]

 5 Induction Motor 6 Speed Detector 7 Speed Detection Circuit 8 Speed Command Circuit 9 PI Control Circuit 10 Limiter Circuit 11 Secondary Flux Pattern Generation Circuit 12 Primary Delay Element 13 Mutual Reactance Pattern Generation Circuit 14 Excitation Current Calculation Circuit 15 Amplitude Calculation Circuit 16 Phase angle calculation circuit 17 Slip angle frequency calculation circuit 18 Primary current reference generation circuit 19 Current control circuit 20 Secondary magnetic flux weakening circuit 22 Changeover switch 23 Changeover switch 24 Changeover switch 25 Positioning sequence circuit 26 Positioning speed command circuit 27 Target position command circuit 28 Position control amplifier 29 Position detection circuit 40 Torque component current command fixing circuit 41 Target stop position arrival detection unit 42 Target stop position arrival detection unit

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[Procedure amendment]

[Submission date] November 19, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction content]

[0001]

BACKGROUND OF THE INVENTION This invention relates to a vector control arithmetic unit for an induction motor, more particularly, those related to the vector control calculating unit for an induction motor can be positioned stop to prevent micro-vibration or hunting There is .

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

(11) is a secondary magnetic flux pattern generation circuit for generating an original secondary magnetic flux φ2 'from the speed detection signal ωr. Reference numeral (20) is a secondary magnetic flux weakening circuit that calculates k · φ2 ′ for the original secondary magnetic flux φ2 ′ and outputs the secondary magnetic flux φ2. As shown in FIG. 5, the constant k is set to <1.0> when the torque component current command iqs * is a predetermined value a or more, and is linear from <1.0> to <b> from the predetermined value a to “0”. Change to. The reason for providing the secondary magnetic flux weakening circuit (20) is as follows. That is, the induction motor (5) generates excitation noise and vibration in proportion to the secondary magnetic flux φ2. These excitation sounds and vibrations are applied to the induction motor (5).
It does not matter when there is a load or when the speed is high , but it becomes noticeable when the load is light or the speed is low.
Therefore, when the load is light or the speed is low, the secondary magnetic flux φ2 is weakened to reduce excitation noise and vibration. For this purpose, a secondary magnetic flux weakening circuit (20) is provided.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

Next, referring to FIG. 6, the positioning stopping operation of the vector control arithmetic unit (100) of the induction motor will be described. Positioning sequence circuit (2
In 5), the changeover switch (22) is turned on, the changeover switch (23) is turned off , and the changeover switch (24) is turned off. At this time, the PI control circuit (9) performs proportional and integral control calculation of the difference between the speed command signal ωr * and the speed detection signal ωr.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0019

[Correction method] Change

[Correction content]

[0019]

In the conventional vector control arithmetic unit (100) for an induction motor, the V-shaped secondary magnetic flux weakening circuit (20) is applied not only during the speed control loop but also during the position control loop. Characteristics work. Therefore, in the vicinity of the target stop position, the secondary magnetic flux command φ2 * changes according to the position deviation. Then, the excitation current command ids * also changes, and the excitation current changes. However, if the excitation current changes corresponding to the position deviation when the position control loop is almost stopped near the target stop position, the induction motor
Since the secondary magnetic flux generated in the machine changes, there is a problem that slight vibration and hunting are likely to occur due to slight position fluctuations.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction content]

The output fixing unit receives the torque component current command iqs * from the limiter circuit (10) as it is before the secondary deviation weakening circuit ( 20). But,
When the comparator unit detects that the positional deviation is equal to or less than the predetermined value even once, the φ2 magnification coefficient k is fixed to the constant value d as shown in FIG. As a result, the secondary magnetic flux φ2 * becomes constant near the target stop position, and the secondary magnetic flux φ2 *
It is possible to prevent a slight vibration or hunting from occurring in the induction motor (5) due to a change in the excitation current due to the change of the.

[Procedure Amendment 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

Embodiment 2 FIG. 3 is a block diagram showing a vector control arithmetic unit (11) for an induction motor according to the present invention. This induction motor vector control arithmetic unit (11) is a secondary magnetic flux weakening circuit (2) of the induction motor vector control arithmetic unit (100) of FIG.
0), a target stop position arrival detection part (41) and a secondary magnetic flux fixing part (42) are added. The target stop position arrival detection unit (41) detects that the target stop position is reached based on the output of the position control amplifier (28). The secondary magnetic flux fixing circuit (42) includes a target stop position arrival detection circuit (4
The secondary magnetic flux φ2 * is fixed based on the detection signal of 1).

[Procedure Amendment 7]

[Document name to be amended] Statement

[Name of item to be corrected] 0030

[Correction method] Change

[Correction content]

As a result, once the target stop position is reached, the secondary magnetic flux φ2 * becomes constant, and the change of the secondary magnetic flux φ2 * causes the excitation component current to fluctuate, causing slight vibration or hunting in the induction motor (5). Is prevented.

Claims (2)

[Claims] 1. A vector control arithmetic unit for an induction motor, wherein a primary current applied to an induction motor is divided into a torque component current and an excitation component current and the ratio of the excitation component current is changed according to the size of a load. Induction, which is provided with a positioning stop control mode detecting means for detecting that the mode is in the mode and an exciting current ratio fixing means for fixing the ratio of the exciting current regardless of the size of the load in the positioning stop control mode. Vector control arithmetic unit for electric motor. 2. A vector control arithmetic unit for an induction motor, wherein the primary current applied to the induction motor is divided into a torque component current and an excitation component current, and the ratio of the excitation component current is changed according to the size of the load. Positioning stop control mode detecting means for detecting the mode, arrival detecting means for detecting arrival near the target stop position, and after reaching the vicinity of the target stop position even once in the positioning stop control mode Is a vector control arithmetic unit for an induction motor, which is provided with an exciting current ratio fixing means for fixing the exciting current ratio regardless of the size of the load.