KR20230149110A - Apparatus for Hybrid Type Induction Motor Drive Control - Google Patents

Abstract

Disclosed is a hybrid type induction motor drive control device capable of minimizing fluctuations of speed even in low-speed sections of a motor by using a hybrid V/F control method. This divides driving sections of the motor into a low-speed section, a medium-speed section, and a high-speed section and applies a different V/F pattern to each section to have linear speed characteristics from the low-speed section to the high-speed section.

Description

Hybrid type induction motor drive control device {Apparatus for Hybrid Type Induction Motor Drive Control}

The present invention relates to a hybrid type induction motor drive control device, and more specifically, to a hybrid type induction motor drive control device that has linear speed characteristics when driving an induction motor.

In general, induction motors are electric motors used in a variety of fields, from fields such as fans and pumps to lifting loads such as cranes and elevators. The induction motor drive control method generally uses a method of controlling speed through V/F (voltage/frequency) control and vector control.

Figure 1 is a graph showing a conventional V/F control method.

Referring to Figure 1, the conventional V/F control method is a scalar control method using a linear function pattern, and is a method that changes the frequency of the induction motor and changes the voltage proportionally at the same time. In other words, when the frequency is lowered to lower the speed of the motor while driving the induction motor, the voltage is proportionally lowered in proportion to the lowered frequency, thereby maintaining the ratio of voltage and frequency constant.

However, in the V/F control method that uses only this first-order function pattern, the voltage and frequency vary in constant proportion, so the voltage drop due to stator resistance and the error between the actual speed and reference speed in the low-speed section where the air gap magnetic flux decreases. This has the disadvantage of causing large speed fluctuations in the low and medium speed sections of the motor.

Korean registered patent 10-1535727

The technical problem to be achieved by the present invention is to provide a hybrid induction motor drive control device that can minimize speed fluctuations even in the low-speed section of the motor using a hybrid V/F control method.

The hybrid type induction motor drive control device of the present invention to solve the above problem includes an angular velocity converter that converts the reference frequency into an angular velocity, a sine wave generator that receives the reference frequency and generates a sine wave according to the reference frequency, and the angular velocity. A V/F generator that receives the converted angular velocity from the conversion unit and generates each V/F pattern according to the driving section of the motor, and selects the V/F pattern generated by the V/F generator to control the motor. It includes a V/F selection unit that determines the operating voltage according to the driving section.

The driving section of the electric motor may include a low-speed section, a medium-speed section, and a high-speed section.

The V/F generator includes a first V/F calculation unit that generates a first V/F pattern operated in the low-speed section, and a second V/F generator that generates a second V/F pattern that operates in the medium-speed section. It may include a calculation unit and a third V/F calculation unit that generates a third V/F pattern operated in the high-speed section.

The first V/F pattern forms a V/F pattern in the form of a quadratic function, the second V/F pattern forms a V/F pattern in the form of a constant function, and the third V/F pattern forms 1 A V/F pattern in the form of a difference function can be formed.

The V/F selection unit includes a first selection unit and a first selection unit for selecting one of the V/F patterns output from the first V/F calculation unit and the second V/F calculation unit, respectively. It may include a second selection unit that selects one of the V/F patterns output from the 2 V/F calculation unit and the first selection unit.

The first VF calculation unit includes a quadratic function generator that receives the angular velocity converted from the angular velocity conversion unit and converts the converted angular velocity into a quadratic function form, and 2 which determines the coefficient of the angular velocity converted into the quadratic function form. It may include a boost voltage generator that outputs a difference coefficient gain and a boost voltage, and a first operator that receives the output of the second coefficient gain and the output of the boost voltage generator, respectively, and generates the first V/F pattern. .

The second VF calculation unit may include a constant function generator for generating the second V/F pattern, and the third VF calculation unit may include a first coefficient gain for generating the third V/F pattern.

A first switch that receives the first V/F pattern and the second V/F pattern and selects one of the input V/F patterns, and the third V/F pattern and the first switch. It may include a second switch that receives the V/F pattern selected by the first switch and selects one of the input V/F patterns.

It may further include a voltage compensator that generates a compensation voltage, and a second operator that receives the compensation voltage and the output signal of the second switch and outputs a driving voltage of the electric motor.

The sine wave generator receives an integrator that converts the reference frequency into a phase, a third operator that calculates the phase converted by the integrator and a matrix input from a matrix generator, and an output signal from the third operator, and outputs a sine wave. It may include a sinusoidal generator.

It may further include a multiplier that receives the sine wave output by the sine wave generator and the driving voltage output by the second operator, and outputs a voltage command according to the driving section of the electric motor.

According to the present invention, the driving section of the electric motor is divided into a low-speed section, a medium-speed section, and a high-speed section, and a different V/F pattern is applied to each section, so that linear speed characteristics can be obtained from the low-speed section to the high-speed section.

Additionally, by using a secondary function pattern in a low-speed section, a higher voltage can be applied than when using a primary function pattern. Therefore, the speed error between the actual speed and the reference speed can be reduced in the low-speed section where the air gap magnetic flux decreases, so the electric motor can be driven stably.

Furthermore, by applying a constant function V/F pattern to the medium-speed section between the low-speed section and the high-speed section, the gap between the non-linear and linear sections can be reduced to ensure that the motor is driven stably.

The technical effects of the present invention are not limited to those mentioned above, and other technical effects not mentioned will be clearly understood by those skilled in the art from the description below.

Figure 1 is a graph showing a conventional V/F control method.
Figure 2 is a block diagram showing a hybrid type induction motor drive control device of the present invention.
Figure 3 is a diagram showing the V/F generation unit of the present invention.
Figure 4 is a diagram showing the V/F selection unit of the present invention.
Figure 5 is a graph showing the voltage and frequency relationship according to the hybrid type induction motor drive control device of the present invention.
Figure 6 is a graph showing the voltage and frequency relationship according to the hybrid type induction motor drive control device of the present invention.
Figure 7 is a diagram comparing measurement results according to the speed output of the hybrid induction motor of the present invention and the conventional induction motor.
Figure 8 is a diagram comparing measurement results according to the voltage output of the hybrid induction motor of the present invention and the conventional induction motor.

Since the present invention can be modified in various ways and can have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all transformations, equivalents, and substitutes included in the spirit and technical scope of the present invention. In describing the present invention, if it is determined that a detailed description of related known technologies may obscure the gist of the present invention, the detailed description will be omitted.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the description with reference to the accompanying drawings, identical or corresponding components will be assigned the same drawing numbers and redundant description thereof will be omitted. Do this.

Example

Figure 2 is a block diagram showing a hybrid type induction motor drive control device of the present invention.

Referring to FIG. 2, the hybrid type induction motor drive control device according to the present invention includes an angular velocity conversion unit 100, a sine wave generator 200, a V/F generator 300, and a V/F selector 400. Includes.

The angular velocity converter 100 receives a reference frequency (f _ref ) from the frequency generator 10 and converts the input reference frequency (f _ref ) into an angular velocity (ω). For example, the angular velocity converter 100 may convert the reference frequency (f _ref ) into the angular velocity (ω) by multiplying the input reference frequency (f _ref ) by 2π.

The sine wave generator 200 receives a reference frequency (f _ref ) and generates a sine wave according to the input reference frequency (f _ref ). The sine wave output through the sine wave generator 200 is converted by a voltage (Vm) determined by the V/F pattern and output to the electric motor (M).

The V/F generator 300 receives the angular velocity (ω) converted from the angular velocity converter 100 and generates each V/F pattern (VF) according to the driving section of the electric motor (M). For example, the conventional V/F control method uses a scalar control method using a linear function pattern to keep the ratio of voltage and frequency constant. However, in the V/F control method that uses only this first-order function pattern, the voltage and frequency vary in constant proportion, so the voltage drop due to stator resistance and the error between the actual speed and reference speed in the low-speed section where the air gap magnetic flux decreases. This has the disadvantage of causing large speed fluctuations in the low and medium speed sections of the motor (M).

Therefore, the hybrid induction motor drive control device according to the present invention has a hybrid V/F control method that mixes a conventional linear function pattern with a secondary function pattern and a constant function pattern. That is, in a low-speed section, a higher voltage can be applied by using a secondary function pattern than when using a primary function pattern. In addition, in the high-speed section, the motor (M) is driven using a linear function pattern, but by adding a constant function pattern in the medium-speed section, the gap between the non-linear and linear sections can be reduced to ensure that the motor (M) is driven stably. there is.

That is, the driving section that controls the electric motor (M) is divided into a low-speed section, a medium-speed section, and a high-speed section, and a quadratic function pattern, a constant function pattern, and a linear function pattern can be applied to each section.

Figure 3 is a diagram showing the V/F generation unit of the present invention.

Referring to FIG. 3, the V/F generating unit 300 according to the present invention includes a first V/F calculating unit 310, a second V/F calculating unit 320, and a third V/F calculating unit 330. ) may include.

The first V/F calculation unit 310 receives the angular velocity (ω) converted from the angular velocity conversion unit 100 and generates a first V/F pattern (VF1). For example, the first V/F pattern VF1 calculated through the first V/F calculation unit 310 may be a quadratic function pattern. That is, the first V/F pattern VF1 may have a curved pattern. The first V/F pattern (VF1) having a quadratic function pattern can be applied to a low-speed section during the driving section of the electric motor (M). By applying the quadratic function pattern to the low-speed section, a higher voltage can be applied than the first-order function pattern in the low-speed section. Therefore, the speed error between the actual speed and the reference speed can be reduced in the low-speed section where the air gap magnetic flux decreases, so the electric motor M can be stably driven.

The second V/F calculation unit 320 generates a second V/F pattern (VF2). For example, the second V/F pattern VF2 may be a constant function pattern. That is, the second V/F pattern VF2 may have a horizontal straight line shape. The second V/F pattern VF2 having a constant function pattern can be applied to a medium-speed section among the driving sections of the electric motor (M).

The third V/F calculation unit 330 receives the angular velocity (ω) converted from the angular velocity conversion unit 100 and generates a third V/F pattern (VF3). For example, the third V/F pattern VF3 may be a linear function pattern. That is, the third V/F pattern VF3 may have a straight line shape with a slope. The third V/F pattern (VF3) having a linear function pattern can be applied to a high-speed section during the driving section of the electric motor (M). Therefore, in the high-speed section, the voltage and frequency may have a linear function form that increases in linear proportion.

The V/F selection unit 400 selects the V/F pattern generated by the V/F generation unit 300 to determine the operating voltage according to the driving section of the electric motor (M). That is, the V/F selection unit 400 includes the first V/F pattern (VF1), the second V/F pattern (VF2), and the third V/F pattern (VF3) generated by the V/F generation unit 300. ), you can select any one pattern and determine the operating voltage according to the selected pattern.

Figure 4 is a diagram showing the V/F selection unit of the present invention.

Referring to FIGS. 3 and 4 , the V/F selection unit 400 may include a first selection unit 410 and a second selection unit 420.

The first selection unit 410 includes a first V/F pattern (VF1) generated by the first V/F calculation unit 310 and a second V/F pattern generated by the second V/F calculation unit 320. (VF2) is input, and any one of these V/F patterns can be selected. For example, in a low-speed section, a first V/F pattern (VF1) having a quadratic function pattern may be selected, and in a medium-speed section, a second V/F pattern (VF2) having a constant function pattern may be selected.

The second selection unit 420 receives the third V/F pattern (VF3) generated in the third V/F calculation unit 330 and the V/F pattern selected in the first selection unit 410, and these You can select any one V/F pattern among the patterns. For example, in a low-speed section, the first V/F pattern (VF1) may be selected in the first selection unit 410, and the first V/F pattern (VF1) may be selected in the second selection unit 420. there is. In the medium speed section, the second V/F pattern (VF2) may be selected in the first selection unit 410, and the second V/F pattern (VF2) may also be selected in the second selection unit 420. In addition, in the high-speed section, even if either the first V/F pattern (VF1) or the second V/F pattern (VF2) is selected in the first selection unit 410, the second selection unit 420 ), the third V/F pattern (VF3) having a linear function pattern may be selected.

That is, each V/F pattern generated through the first V/F calculation unit 310, the second V/F calculation unit 320, and the third V/F calculation unit 330 is that of the electric motor (M). Depending on the driving section, it can be appropriately selected by the first selection unit 410 and the second selection unit 420. In addition, the corresponding operating voltage is determined according to the selected V/F pattern, and is calculated as a voltage command with a voltage magnitude and frequency appropriate for each driving section by the determined operating voltage and the sine wave generated by the sine wave generator 200. and can be transmitted to the electric motor (M).

Figure 5 is a configuration diagram for explaining the hybrid type induction motor drive control device of the present invention.

Referring to Figure 5, in the hybrid type induction motor drive control device according to the present invention, when the reference frequency (f _ref ) is input as the gain (101) by the frequency generator (10), the reference frequency (f _ref ) is angular velocity. It is converted to (ω). The quadratic function generator 311 receives the converted angular velocity (ω), converts the angular velocity (ω) into a quadratic function form (ω ² ), and generates a quadratic coefficient gain 312 that determines the coefficient of the quadratic function. It is output to the first operator 314. For example, by adjusting the coefficient through the quadratic coefficient gain 312, the width of the quadratic function curve can be adjusted.

The first operator 314 receives the angular velocity in the form of a quadratic function with a selected coefficient and the boost voltage (V _B ) generated by the boost voltage generator 313, and generates a first V/F pattern (VF1) in the form of a quadratic function. can be created. At this time, the coefficient of the quadratic function and the boost voltage (V _B ) may be selected to suit the load characteristics. For example, when a relatively large initial starting torque is required, a V/F pattern in which the initial voltage is increased by increasing the boost voltage to secure starting from the beginning can be applied.

The first V/F pattern (VF1) output through the first operator 314 is connected to the first switch 411 together with the second V/F pattern (VF2) in the form of a constant function generated by the constant function generator 321. It can be entered as . The first switch 411 receives the first V/F pattern (VF1), the second V/F pattern (VF2), and the converted angular velocity (ω), and switches the first V/F pattern (VF1) and the converted angular velocity (ω) according to the driving section of the electric motor (M). One of the F pattern (VF1) and the second V/F pattern (VF2) can be selected. The selected V/F pattern is output to the second switch 421.

The first coefficient gain 331 may receive the converted angular velocity (ω) and generate a third V/F pattern (VF3) in the form of a first order function. At this time, the coefficient of the first-order function can be determined through the first-order coefficient gain 331. For example, by adjusting the coefficient through the first coefficient gain 331, the slope of the first function can be determined.

The third V/F pattern (VF3) generated through the first coefficient gain 331 is sent to the second switch 421 together with the V/F pattern selected through the first switch 411 and the converted angular velocity ω. can be entered. The second switch 421 selects one of the V/F patterns selected through the third V/F pattern (VF3) and the first switch 411 according to the driving section of the electric motor (M), and , the selected V/F pattern is output to the second operator 510. The second calculator 510 may determine the magnitude of the driving voltage according to frequency using the V/F pattern selected through the second switch 421 and the voltage (V _com ) input through the voltage compensator 20.

Meanwhile, the integrator 210 of the sine wave generator 200 receives a reference frequency (f _ref ) and converts the input reference frequency (f _ref ) into a phase (θ). The third operator 230 receives the converted phase (θ) through the integrator 210 and the matrix generated by the matrix generator 220, calculates the phase (θ) and matrix, and outputs them to the sine wave generator 240. . The sinusoidal wave generated through the sinusoidal generator 240 is input to the multiplier 520 together with the driving voltage (Vm) output by the second operator 510, and a voltage command having a voltage magnitude and frequency appropriate for the driving section is provided to the motor. It is output as (M).

Figure 6 is a graph showing the voltage and frequency relationship according to the hybrid type induction motor drive control device of the present invention.

Referring to FIG. 6, different driving patterns may be applied depending on the driving section of the hybrid induction motor driving control device according to the present invention. For example, in the low speed section (0~ω ₁ ), a curved pattern that is the first V/F pattern (VF1) in the form of a quadratic function is applied, and in the medium speed section (ω ₁ ~ω ₂ ), the second V in the form of a constant function is applied. A straight line pattern, which is the /F pattern (VF2), is applied, and in the high-speed section (ω ₂ ~), a straight line pattern with a slope, which is the third V/F pattern (VF3) in the form of a linear function, can be applied.

At this time, the amount of change in the width of the curved pattern applied to the low-speed section and the slope of the straight line pattern applied to the high-speed section can be adjusted to suit the load characteristics.

For example, in a low-speed section, the boost voltage (V _B ) and the first V/F pattern (VF1) may be applied. That is, in a low-speed section, a higher voltage can be applied by using a secondary function pattern than when using a primary function pattern. Therefore, it is possible to prevent a voltage drop due to stator resistance and an error between the actual speed and the reference speed in the low-speed section where the conventional air gap magnetic flux decreases. For example, the range to which the low speed section is applied may have a range of 0≤ω≤31.368.

In the high-speed section, the third V/F pattern (VF3) can be applied. For example, the quadratic function pattern applied in the low-speed section to secure the initial starting torque may generate overcurrent because a voltage exceeding the required torque is applied in the mid- and high-speed sections, and this overcurrent may cause drive loss, deteriorating driving performance. This may deteriorate. Therefore, in order to prevent this problem, the third V/F pattern (VF3) in the form of a linear function is applied in the high-speed section. For example, the range to which the high-speed section is applied may have a range of 125.66≤ω.

The second V/F pattern (VF2) may be applied to the medium-speed section, which is the section between the low-speed section and the high-speed section. For example, if a high-speed section to which a first-order function pattern is applied is used immediately after a low-speed section to which a quadratic function pattern is applied, the gap between the non-linear section and the linear section is bound to be large. Accordingly, by applying the second V/F pattern VF2 in the form of a constant function to the medium-speed section between the low-speed section and the high-speed section, the gap between the non-linear low-speed section and the linear high-speed section can be reduced. For example, the range to which the medium speed section is applied may be 31.368≤ω≤125.66.

As described above, the driving section of the electric motor (M) is divided into a low-speed section, a medium-speed section, and a high-speed section, and a different V/F pattern is applied to each section, so that linear speed characteristics can be obtained from the low-speed section to the high-speed section. Therefore, it can be applied to various loads.

Figure 7 is a diagram comparing the measurement results according to the speed output of the hybrid induction motor of the present invention and the conventional induction motor.

Here, Figure 7(a) is a graph measuring the speed output of a conventional induction motor using only the linear function V/F pattern, and Figure 7(b) is a graph measuring the speed output of the hybrid type induction motor of the present invention. .

Referring to Figures 7(a) and 7(b), the conventional induction motor using only the linear function V/F pattern has a large speed change in the actual speed (n _m ) in the low speed section of 0.9 s. You can check what is happening.

However, the hybrid induction motor of the present invention, which uses different V/F patterns in the low-speed section, medium-speed section, and high-speed section, uses a quadratic function V/F pattern in the low-speed section to apply a high voltage, By reducing the gap between the non-linear low-speed section and the linear high-speed section by using the constant function V/F pattern in the medium-speed section, it can be confirmed that the actual speed (n _m ) has linear speed characteristics.

Figure 8 is a diagram comparing measurement results according to the voltage output of the hybrid induction motor of the present invention and the conventional induction motor.

Here, Figure 8(a) is a graph measuring the voltage output (V _a ) of a conventional induction motor using only the linear function V/F pattern, and Figure 8(b) is a graph measuring the voltage output (V a ) of the hybrid type induction motor of the present invention ( This is a graph measuring V _b ).

Referring to FIGS. 8(a) and 8(b), compared to an induction motor using only a conventional linear function V/F pattern with a rated voltage of 380V, this motor uses a different V/F pattern for each driving section. It can be confirmed that the hybrid type induction motor of the invention also has an output voltage within the rated voltage of 380V.

As described above, the hybrid type induction motor drive control device according to the present invention divides the driving section of the electric motor into a low-speed section, a medium-speed section, and a high-speed section, and applies a different V/F pattern to each section, starting from the low-speed section to the high-speed section. It can have linear speed characteristics up to the section. Additionally, by using a secondary function pattern in a low-speed section, a higher voltage can be applied than when using a primary function pattern. Therefore, the speed error between the actual speed and the reference speed can be reduced in the low-speed section where the air gap magnetic flux decreases, so the electric motor can be driven stably. Furthermore, by applying a constant function V/F pattern to the medium-speed section between the low-speed section and the high-speed section, the gap between the non-linear and linear sections can be reduced to ensure that the motor is driven stably.

Meanwhile, the embodiments of the present invention disclosed in the specification and drawings are merely provided as specific examples to aid understanding, and are not intended to limit the scope of the present invention. It is obvious to those skilled in the art that in addition to the embodiments disclosed herein, other modifications based on the technical idea of the present invention can be implemented.

100: Angular velocity conversion unit 200: Sine wave generation unit
300: V/F generation unit 310: First V/F calculation unit
320: 2nd V/F calculation unit 330: 3rd V/F calculation unit
400: V/F selection part 410: first selection part
420: Second selection VF1: First VF pattern
VF2: 2nd VF pattern VF3: 3rd VF pattern

Claims (11)

An angular velocity converter that converts the reference frequency into an angular velocity;
a sine wave generator that receives the reference frequency and generates a sine wave according to the reference frequency;
a V/F generator that receives the angular velocity converted from the angular velocity converter and generates each V/F pattern according to the driving section of the electric motor; and
A hybrid induction motor drive control device including a V/F selection unit that selects the V/F pattern generated in the V/F generation unit to determine an operating voltage according to a driving section of the motor. According to paragraph 1,
A hybrid type induction motor drive control device wherein the driving section of the electric motor includes a low-speed section, a medium-speed section, and a high-speed section. The method of claim 2, wherein the V/F generator,
a first V/F calculation unit that generates a first V/F pattern operated in the low-speed section;
a second V/F calculation unit that generates a second V/F pattern operated in the medium speed section; and
A hybrid induction motor drive control device including a third V/F calculation unit that generates a third V/F pattern operated in the high-speed section. According to paragraph 3,
The first V/F pattern forms a V/F pattern in the form of a quadratic function,
The second V/F pattern forms a V/F pattern in the form of a constant function,
The third V/F pattern is a hybrid induction motor drive control device that forms a V/F pattern in the form of a linear function. The method of claim 3, wherein the V/F selection unit,
a first selection unit that selects one of the V/F patterns output from the first V/F calculation unit and the second V/F calculation unit; and
A hybrid type induction motor drive control device comprising a second selection unit that selects one of the V/F patterns output from the second V/F calculation unit and the first selection unit, respectively. The method of claim 3, wherein the first VF calculation unit,
a quadratic function generator that receives the converted angular velocity from the angular velocity conversion unit and converts the converted angular velocity into a quadratic function;
a quadratic coefficient gain that determines the coefficient of the angular velocity converted to the quadratic function form;
A boost voltage generator outputting a boost voltage; and
A hybrid induction motor driving control device comprising a first operator that receives the output of the secondary coefficient gain and the output of the boost voltage generator, respectively, and generates the first V/F pattern. According to clause 6,
The second VF calculation unit includes a constant function generator that generates the second V/F pattern,
The third VF calculation unit is a hybrid induction motor driving control device including a first coefficient gain for generating the third V/F pattern. In clause 7,
a first switch that receives the first V/F pattern and the second V/F pattern and selects one of the input V/F patterns; and
A hybrid induction motor comprising a second switch that receives the third V/F pattern and the V/F pattern selected by the first switch and selects one of the input V/F patterns. Drive control device. According to clause 8,
a voltage compensator that generates a compensation voltage; and
A hybrid induction motor driving control device further comprising a second operator that receives the compensation voltage and the output signal of the second switch and outputs a driving voltage of the motor. The method of claim 9, wherein the sinusoidal wave generator,
an integrator converting the reference frequency into phase;
a third operator that calculates the phase converted by the integrator and the matrix input from the matrix generator; and
A hybrid induction motor drive control device comprising a sine wave generator that receives the output signal of the third calculator and outputs a sine wave. According to clause 10,
A hybrid induction motor drive control device further comprising a multiplier that receives the sine wave output by the sine wave generator and the driving voltage output by the second operator, and outputs a voltage command according to the driving section of the motor.