KR20150062046A - Induction motor drive device and regeneration torque suppression method thereof - Google Patents

Abstract

An induction motor drive device according to an embodiment of the present invention comprises: a flux observer unit to determine the rotor flux based on an output voltage and an output current supplied to an induction motor; a torque calculation unit to determine output torque of the induction motor based on the rotor flux; and a torque control unit to determine a compensation quantity for an output frequency used in determining the output voltage based on the output torque.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction motor drive apparatus and a regenerative torque suppression method,

The present invention relates to an induction motor drive apparatus and a regenerative torque suppressing method thereof.

The induction motor drive controls the magnitude of the output torque according to the torque generation of the load machine in order to keep the speed of the induction motor at the desired speed. That is, when a reduction torque is generated in a load machine, an induction motor drive device generates an acceleration torque to maintain the speed of the induction motor, and when an acceleration torque is generated in the load machine, a deceleration torque is generated in the induction motor drive device, .

However, when the decelerating torque is generated in the induction motor drive apparatus as described above, the regenerative energy is introduced from the induction motor to the inverter of the induction motor drive apparatus and the DC voltage rises, thereby causing an overvoltage trip to the induction motor drive apparatus .

Further, when an additional device (for example, a resistor and a switch) is added to the induction motor driving apparatus to solve this problem, there is a problem that additional cost is incurred and energy efficiency is lowered.

In order to solve the above problems, there is a demand for an induction motor drive apparatus and a regenerative torque suppressing method thereof.

An induction motor drive apparatus according to an embodiment of the present invention includes a magnetic flux observing unit for determining a rotor magnetic flux based on an output voltage and an output current provided by an induction motor and an output of the induction motor based on the determined rotor flux, A torque calculator for determining a torque and a torque controller for determining a compensation amount of an output frequency used for determining the value of the output voltage based on the determined output torque.

An induction motor drive apparatus according to an embodiment of the present invention includes an acceleration / deceleration section for determining an output frequency in accordance with a frequency command, and a control section for determining a value of an output voltage based on an output frequency determined by the acceleration / deceleration section, And a voltage control unit for providing an output voltage to the induction motor, wherein the torque control unit performs a proportional-integral control so that the determined output torque is '0' to determine a compensation amount of the output frequency.

In the induction motor drive apparatus according to the embodiment of the present invention, the torque calculating section determines the current speed of the induction motor on the basis of the determined rotor magnetic flux, and the torque control section sets the determined output frequency compensation amount and the induction motor And a final output frequency compensation amount is determined according to the calculation result.

In the induction motor drive apparatus according to the embodiment of the present invention, when the calculation result is positive, the torque control section determines that the output torque is the regenerative torque, determines the final output frequency compensation amount at the determined output frequency compensation amount , And determines that the output torque is not the regenerative torque and determines the final output frequency compensation amount to be '0' if the calculation result is not a positive number.

A regeneration torque suppressing method of an induction motor drive apparatus according to an embodiment of the present invention includes the steps of determining a rotor magnetic flux based on an output voltage and an output current provided by an induction motor, Determining an output torque of the electric motor; and determining a compensation amount of an output frequency used for determining the value of the output voltage based on the determined output torque.

A method for suppressing regenerative torque in an induction motor drive apparatus according to an embodiment of the present invention includes the steps of determining an output frequency according to a frequency command, determining a value of an output voltage based on the determined output frequency, And providing the output voltage to the induction motor, wherein the output frequency compensation amount is determined by performing a proportional-integral control so that the determined output torque is '0'.

A method of controlling a regenerative torque of an induction motor drive apparatus according to an embodiment of the present invention includes the steps of determining a current speed of an induction motor based on the determined rotor magnetic flux, And determining a final output frequency compensation amount according to a calculation result.

In the regenerative torque suppressing method of an induction motor drive apparatus according to an embodiment of the present invention, the final output frequency compensation amount determining step determines that the output torque is a regenerative torque if the calculation result is positive, And determining a final output frequency compensation amount as 0 if the calculation result is not a positive number, and determining that the output torque is not a regenerative torque, and determining a final output frequency compensation amount as '0' can do.

An induction motor drive apparatus and a regenerative torque suppressing method thereof may be provided.

1 is a diagram showing an internal circuit of an induction motor drive apparatus according to an embodiment of the present invention,
2 is a block diagram showing a detailed configuration of a control unit in an induction motor drive apparatus according to an embodiment of the present invention, and Fig.
3 is a flowchart showing a regenerative torque suppressing method of an induction motor drive apparatus according to an embodiment of the present invention.

It is noted that the technical terms used herein are used only to describe specific embodiments and are not intended to limit the invention. It is also to be understood that the technical terms used herein are to be interpreted in a sense generally understood by a person skilled in the art to which the present invention belongs, Should not be construed to mean, or be interpreted in an excessively reduced sense. Further, when a technical term used herein is an erroneous technical term that does not accurately express the spirit of the present invention, it should be understood that technical terms that can be understood by a person skilled in the art are replaced. In addition, the general terms used in the present invention should be interpreted according to a predefined or prior context, and should not be construed as being excessively reduced.

Also, the singular forms "as used herein include plural referents unless the context clearly dictates otherwise. In the present application, the term "comprises," "comprising," or " comprising ", etc. should not be construed as necessarily including the various components or steps described in the specification, Or some steps may not be included, or may be interpreted to include additional components or steps.

Also, suffixes "module", "unit" and "part" for the components used in the present specification are given or mixed in consideration of ease of specification, and each component having its own distinct meaning or role no.

Furthermore, terms including ordinals such as first, second, etc. used in this specification can be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals refer to like or similar elements throughout the several views, and redundant description thereof will be omitted.

In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. It is to be noted that the accompanying drawings are only for the purpose of facilitating understanding of the present invention, and should not be construed as limiting the scope of the present invention with reference to the accompanying drawings.

Hereinafter, the present invention relates to an induction motor drive apparatus and a regenerative torque suppressing method thereof.

1 is a diagram showing an internal circuit of an induction motor drive apparatus according to an embodiment of the present invention.

Referring to FIG. 1, the induction motor drive apparatus includes a controller 100 and an inverter 110.

The control unit 100 outputs a gate signal to the inverter 110 and controls the inverter 110 to provide the output voltage of the value determined according to the output frequency to the induction motor 120. The control unit 100 determines the output torque of the induction motor 120 based on the output voltage and the output current provided to the induction motor 120 from the inverter 110 and outputs the output torque And controls the output torque of the induction motor 120 to be within the torque limit value.

The inverter 110 is comprised of a plurality of power devices Q1 to Q6 and a plurality of power devices Q1 to Q6 are turned on and off according to a gate signal from the controller 100, 120) to provide a voltage (V _abcs, i.e. _as V, V _bs, V _cs) and a current (I _abcs, i.e., _as I, I _bs, I _cs) of the three-phase (phase) having a phase difference of 120 degrees.

2 is a block diagram showing the detailed configuration of the control unit 100 in the induction motor drive apparatus according to the embodiment of the present invention.

2, the controller 200 of the induction motor drive apparatus includes an acceleration / deceleration unit 202, a voltage control unit 204, a magnetic flux observing unit 206, a torque calculation unit 208, and a torque control unit 210 do.

The acceleration / deceleration unit 202 determines the output frequency F _r in accordance with a frequency command input from the user during operation of the induction motor 230.

The voltage control unit 204 determines the output voltage value based on the output frequency determined by the acceleration / deceleration unit 202 and provides the output voltage of the determined value to the induction motor 230 through the inverter 220 do. That is, the voltage controller 204 outputs a gate signal to the inverter 220 and controls the inverter 220 to provide the output voltage of the determined value to the induction motor 230. Here, the inverter 220 is composed of a plurality of power devices Q1 to Q6, and a plurality of power devices Q1 to Q6 are turned on / off according to a gate signal from the voltage controller 204, provides a voltage (V _abcs, i.e. V _as, V _bs, V _cs) and a current (I _abcs, i.e. I _as, I _bs, I _cs) of the three-phase (phase) having a phase difference of 120 degrees to the electric motor 230 .

The flux observer 206 determines the rotor flux based on the output voltage and the output current provided from the voltage controller 204 to the induction motor 230 via the inverter 220. [ Specifically, the flux observing unit 206 calculates a three-phase output voltage V _abcs (i.e., V _as , V _bs , V _cs ) on the three-phase coordinate system (i.e., ABC coordinate system) provided to the induction motor 230, and converted to the value of the output current (I _abcs, i.e. I _as, I _bs, I _cs) to obtain the value, the output voltage (V _ds, V _qs) and output current (I _ds, I _qs) on the DQ rotating coordinates of (V _ds , V _qs ) and output current (I _ds , I _qs ) on the DQ stationary coordinate system using the stator voltage equation and the rotor voltage equation of the induction motor. lambda _dr , lambda _qr ).

The magnetic flux observer 206 may calculate the magnetic flux based on the values of the rotor fluxes? _Dr and? _Qr and the output currents I _ds and I _qs on the determined DQ stationary coordinate system, Similarly, the q-axis current (I _qe ) on the DQ synchronous coordinate system is determined.

The torque computing unit 208 determines an output torque of the induction motor 230 based on the determined rotor magnetic flux and the q-axis current. More specifically, the number of poles (MotorPole) of said torque computing section 208, on the DQ rotating coordinates rotor flux (λ _dr, λ _qr) and the q-axis current on the DQ synchronous coordinate system (I _qe), the induction motor 230, The output torque T _q of the induction motor 230 is determined based on the mutual inductance L _m and the rotor inductance L _r as shown in Equation (2) below.

를 결정할 수 있다. Further, the torque computing unit 208 determines the current speed of the induction motor 230 based on the determined rotor magnetic flux. For example, by differentiating the phase of the determined rotor magnetic flux, the speed of the current induction motor 230

Can be determined.

)을 결정한다. 상세히 설명하면, 상기 결정된 출력토크와 토크제한값 '0'의 오차를 입력으로 하는 비례적분 제어기를 이용하여 상기 출력주파수의 보상량을 결정한다. The torque control unit 210 determines a compensation amount of the output frequency used for determining the value of the output voltage based on the determined output torque. At this time, the torque control unit 210 performs proportional-integral control so that the determined output torque is '0', as shown in Equation (3) below,

). In more detail, the compensation amount of the output frequency is determined by using a proportional integral controller that receives the determined output torque and the error of the torque limit value '0'.

는 상기 출력주파수의 보상량을 의미하고, K_p는 비례이득을 의미하며, T_q는 상기 결정된 출력토크를 의미하고, K_i는 적분이득을 의미한다. here,

Denotes a compensation amount of the output frequency, K _p denotes a proportional gain, T _q denotes the determined output torque, and K _i denotes an integration gain.

)을 결정한다. 즉, 상기 토크제어부(210)는, 계산 결과가 양수이면, 상기 출력토크가 회생토크라고 판단하고, 상기 결정된 출력주파수 보상량으로 최종 출력주파수 보상량을 결정하며, 계산 결과가 양수가 아니면, 상기 출력토크가 회생토크가 아니라고 판단하고, 최종 출력주파수 보상량을 '0'으로 결정한다. Further, the torque control unit 210 calculates a product of the determined output frequency compensation amount and the induction motor speed, and calculates a final output frequency compensation amount (

). That is, if the calculation result is positive, the torque control unit 210 determines that the output torque is a regenerative torque, determines the final output frequency compensation amount at the determined output frequency compensation amount, and if the calculation result is not a positive number, It is determined that the output torque is not the regenerative torque, and the final output frequency compensation amount is determined as " 0 ".

Also, the torque control unit 210 compensates the output frequency determined by the acceleration / deceleration unit 202 with the determined final output frequency compensation amount. Accordingly, the determined final output frequency compensation amount is added to the output frequency determined by the acceleration / deceleration section 202 and supplied to the voltage control section 204. [

3 is a flowchart showing a regenerative torque suppressing method of an induction motor drive apparatus according to an embodiment of the present invention.

Referring to FIG. 3, the acceleration / deceleration unit of the induction motor drive apparatus determines an output frequency according to a frequency command input from a user during operation of the induction motor in step 301. [

Then, the voltage controller of the induction motor drive apparatus determines the output voltage value based on the determined output frequency in step 303, and provides the output voltage of the determined value to the induction motor through the inverter. That is, the voltage controller outputs a gate signal to the inverter and controls the inverter to provide the output voltage of the determined value to the induction motor. Here, the inverter is composed of a plurality of power devices Q1 to Q6, and the plurality of power devices Q1 to Q6 are turned on / off according to the gate signal from the voltage controller, having provides a voltage (V _abcs, i.e. _as V, V _bs, V _cs) and a current (I _abcs, i.e., _as I, I _bs, I _cs) on the third.

Then, the flux observing unit of the induction motor driving apparatus determines the rotor flux based on the output voltage and the output current value provided to the induction motor in step 305. In detail, the flux observer _monitors the three-phase output voltage V _abcs (i.e., V _as , V _bs , V _cs ) on the three-phase coordinate system (i.e., ABC coordinate system) provided to the induction motor through the inverter, and converted to the value of the output current (I _abcs, i.e. I _as, I _bs, I _cs) to obtain the value, the output voltage (V _ds, V _qs) and output current (I _ds, I _qs) on the DQ rotating coordinates of (V _ds , V _qs ) and output current (I _ds , I _qs ) on the DQ stationary coordinate system using the stator voltage equation and the rotor voltage equation of the induction motor. lambda _dr , lambda _qr ). The flux observing unit may calculate the DQ synchronism based on the values of the rotor fluxes (? _Dr ,? _Qr ) and the output currents (I _ds , I _qs ) on the determined DQ stationary coordinate system, The q-axis current (I _qe ) on the coordinate system is determined.

The torque calculating unit of the induction motor driving apparatus determines the output torque of the induction motor and the speed of the current induction motor based on the determined rotor flux and the q-axis current in step 307. [ More specifically, the torque calculating section, the number of poles of on the DQ rotating coordinates rotor flux (λ _dr, λ _qr) and the q-axis current on the DQ synchronous coordinate system (I _qe), the induction motor (MotorPole), mutual inductance (L _m) The output torque T _q of the induction motor is determined based on the rotor inductance L _r , as shown in Equation (2). Further, the torque calculating unit may determine the speed of the current induction motor by differentiating the determined phase of the rotor flux.

In step 309, the torque control unit of the induction motor drive apparatus determines a compensation amount of the output frequency used for determining the value of the output voltage based on the determined output torque. At this time, the torque control unit performs proportional integral control so that the determined output torque becomes '0' as in Equation (3) to determine a compensation amount of the output frequency. In more detail, the compensation amount of the output frequency is determined by using a proportional integral controller that receives the determined output torque and the error of the torque limit value '0'.

In step 311, the torque control unit of the induction motor drive apparatus calculates a product of the determined output frequency compensation amount and the induction motor speed, and checks whether or not the calculation result is positive.

If the calculation result is positive in step 311, the torque control unit of the induction motor drive apparatus determines that the output torque is the regenerative torque in step 313 and determines the final output frequency compensation amount at the determined output frequency compensation amount.

On the other hand, if the calculation result is not positive in step 311, the torque controller of the induction motor drive apparatus determines that the output torque is not the regenerative torque in step 315, and determines the final output frequency compensation amount as '0'.

Here, the fact that the determined output torque and the current induction motor speed have different signs (+, -) means that the regenerative energy is flowing from the induction motor to the inverter of the induction motor drive apparatus. Therefore, if the determined output torque is negative, the determined output frequency compensation amount will be determined as a positive number according to Equation (3), and if the current induction motor speed is positive as opposed to the output torque, The product of the induction motor speed will be determined as a positive number, which indicates that the determined output torque is the regenerative torque. Conversely, if the current induction motor speed is negative as the output torque, the product of the determined output frequency compensation amount and the induction motor speed will be determined to be negative, which indicates that the determined output torque is not the regenerative torque.

Then, in step 317, the torque control unit of the induction motor drive apparatus compensates the output frequency determined by the acceleration / deceleration unit to the determined final output frequency compensation amount. Accordingly, the determined final output frequency compensation amount is added to the output frequency determined by the acceleration / deceleration section, and is provided to the voltage control section.

Thereafter, the induction motor drive apparatus ends the algorithm according to the present invention.

The output torque of the induction motor is within the torque limit value through repetition of each step in FIG. That is, when the output torque of the induction motor does not exist within the torque limit value, the output torque can be adjusted by compensating the output frequency so that the output torque can exist within the torque limit value. Here, the responsiveness of the output torque is adjusted through the proportional gain and the integral gain.

As described above, the induction motor drive apparatus and the regenerative torque suppression method according to the embodiment of the present invention determine the output torque of the induction motor based on the output voltage and the output current provided by the induction motor, Thus, by controlling the output torque of the induction motor to be within the torque limit value by compensating the output frequency, only the output frequency can be changed without any additional device to suppress the inflow of the regenerative energy from the induction motor, There is an advantage that the overvoltage trip of the induction motor drive apparatus can be suppressed. In addition, since no additional apparatus is added, there is no additional cost burden, and there is an advantage that a decrease in energy efficiency can be prevented.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Therefore, the spirit of the present invention should not be construed as being limited to the above-described embodiments, and all of the equivalents or equivalents of the claims, as well as the following claims, I will say.

100:
110: Inverter
120: Induction motor
200:
202: Acceleration /
204:
206: Flux Observation Unit
208:
210:
220: Inverter
230: Induction motor

Claims (8)

A flux observer for determining a flux magnetic flux based on an output voltage and an output current provided by the induction motor;
A torque calculating unit for determining an output torque of the induction motor based on the determined rotor magnetic flux;
And a torque control section that determines a compensation amount of an output frequency used for determination of the value of the output voltage based on the determined output torque.
The method according to claim 1,
An acceleration / deceleration section for determining an output frequency according to a frequency command,
And a voltage control unit for determining a value of the output voltage based on the output frequency determined by the acceleration / deceleration unit and providing the output voltage of the determined value to the induction motor,
Wherein the torque control unit performs proportional integral control so that the determined output torque becomes '0' to determine a compensation amount of the output frequency.
3. The method of claim 2,
Wherein the torque calculating unit determines a current induction motor speed based on the determined rotor flux,
Wherein the torque control unit calculates a product of the determined output frequency compensation amount and an induction motor speed and determines a final output frequency compensation amount according to the calculation result.
The torque control apparatus according to claim 3,
Determines that the output torque is a regenerative torque and determines a final output frequency compensation amount based on the determined output frequency compensation amount if the calculation result is positive,
And determines that the output torque is not a regenerative torque, and determines a final output frequency compensation amount as " 0 " if the calculation result is not a positive number.
Determining a rotor flux based on an output voltage and an output current provided to the induction motor;
Determining an output torque of the induction motor based on the determined rotor flux;
And determining a compensation amount of an output frequency used for determination of the value of the output voltage based on the determined output torque.
6. The method of claim 5,
Determining an output frequency according to a frequency command,
Determining an output voltage value based on the determined output frequency and providing the output voltage of the determined value to an induction motor,
Wherein the output frequency compensation amount is determined by performing proportional-integral control so that the determined output torque becomes " 0 ".
The method according to claim 6,
Determining a current speed of the induction motor based on the determined rotor flux;
Calculating a product of the determined output frequency compensation amount and an induction motor speed, and determining a final output frequency compensation amount according to a calculation result.
The method of claim 7, wherein the final output frequency compensation amount determination step comprises:
Determining that the output torque is a regenerative torque and determining a final output frequency compensation amount based on the determined output frequency compensation amount if the calculation result is positive;
And determining that the output torque is not a regenerative torque and determining a final output frequency compensation amount to be '0' if the calculation result is not a positive number.

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