JP2002034290A - Controlling device of induction motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a controlling device that stably operates an induction motor by an inverter without using any speed detectors. SOLUTION: The input current of an inductor motor is detected, the input current is subjected to 3ϕ/2ϕ conversion for calculating the torque content current of the induction motor by a 3ϕ/2ϕ converter 12, the vibration constituent of the torque content current is taken out by a high-pass filter according to the torque content current calculated by the 3ϕ/2ϕ converter 12, the amount of frequency correction is calculated according to the vibration constituent at a gain operation part, the amount of frequency correction is subtracted from a frequency command inputted from the outside for calculating an output frequency command. a voltage command value corrected by the amount of frequency correction based on the frequency command and is outputted, three- phase voltage reference is outputted based on the voltage command value and output frequency command for controlling the output of an inverter 7, and vibration is inhibited and controlled for stable operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for stably operating an induction motor with an inverter without adding a speed detector.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram of a control system for stably operating an induction motor by a conventional inverter. In the figure, reference numeral 1 denotes a speed command ωr ^* and a speed ωr of an induction motor IM2.
Deviation detector for detecting a deviation .omega.r _err and, 3 slip frequency estimation value IM2 from the deviation .omega.r _err deviation detector 1 omega
Proportional-integral operation (PI) section for estimating s ₁ , 4 for PI section 3
Adder 5 for calculating output frequency command ω _{0 based} on slip frequency estimated value ωs ₁ and speed ωr of IM 2,
The output frequency command omega V / F controller for calculating an arbitrary voltage command V ^* by _0, the output frequency command omega ₀ of 6 adders 4
And a voltage command V ^* of the V / F controller 5 to calculate a three-phase sine wave voltage reference _VU ^* , _VV ^* , _VW ^* . three-phase sinusoidal voltage reference _{^{V U *, V V *,}} V W * by three-phase voltage V _U applied to IM2, _V V, V _W, an inverter unit for outputting, 2 three-phase voltage Vu of the inverter unit 7 , Vv,
Induction motor (IM) driven by Vw, 8 is IM2
Is a speed detector for detecting the speed ωr.

Next, the operation will be described. In the control system configuration shown in FIG. 6, when IM2 being operated by the inverter unit 7 becomes unstable, the speed command ω is given to IM2.
A slip frequency ωs ₁ is generated based on the difference between r ^* and the speed ωr. At this time, the deviation detector 1 detects a deviation ωr _err between the speed command ωr ^* and the speed ωr of the IM2, and the PI unit 3
At up deviation .omega.r _err becomes 0, the slip frequency estimate .omega.s ₁ ^* is changed, the adder 4 at the slip frequency .omega.s ₁ ^*
When the output frequency command omega ₀ from the speed ωr of IM2 is calculated. Thus, in the conventional method, the speed command ωr ^*
Since the speed feedback control system is configured so that the second speed ωr matches, the induction motor can be operated stably.

[0004]

SUMMARY OF THE INVENTION Conventional induction motors are cheaper.
In order to perform constant control, as shown in FIG.
It is necessary to specially install the speed detector 8 for detecting
Was. If the speed detector 8 fails or malfunctions,
Is the speed ωr input to the deviation detector 1 is the actual speed of IM2
In contrast, the control configuration of FIG.
The degree ωr is the speed command ωr ^*Good operating characteristics
There was a problem that would not be.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a control device for stably operating an induction motor by an inverter without using a speed detector.

[0006]

A control device for an induction motor according to the present invention is a control device for an induction motor which drives and controls an induction motor having no speed detector via an inverter. Current detector to detect,
A 3φ / 2φ converter that converts the detection current of this current detector into 3φ / 2φ and calculates a current corresponding to the torque of the induction motor, 3φ
A filter for extracting a vibration component of the torque component current from the torque component current calculated by the / 2φ converter, a frequency correction component calculation unit having a gain calculation unit for calculating a frequency correction component from the vibration component, a frequency command input from the outside Subtractor for calculating the output frequency command by subtracting the frequency correction value from the above, a V / F controller for outputting a voltage command value corrected by the frequency correction value based on the frequency command, and the voltage command value and the output A phase voltage reference signal generator that outputs a three-phase voltage reference based on a frequency command and controls the output of the inverter is provided, and controls to operate stably by suppressing vibration.

Further, in a control device for an induction motor which drives and controls an induction motor having no speed detector via an inverter, a current detector for detecting an input current of the induction motor, and a detection current of the current detector is set to 3φ. 3φ / 2φ converter that calculates the current corresponding to the torque of the induction motor by converting the current to / 2φ,
A filter for extracting a vibration component of the torque component current from the torque component current calculated by the 3φ / 2φ converter, a frequency correction component calculation unit having a gain calculation unit for calculating a frequency correction component from the vibration component, and a frequency input from the outside V that outputs a voltage command value corrected by the frequency correction based on the command
/ F controller, and a phase voltage reference signal generator that outputs a three-phase voltage reference based on the voltage command value and controls the output of the inverter, and controls the operation to suppress vibration and operate stably. is there.

[0008] Further, the frequency correction component calculation unit has a 3φ / 2
It has a weight function generator that weights the torque current calculated by the φ converter in accordance with a frequency command or an output frequency command.

Further, the filter for extracting the vibration component of the torque current is a band-pass filter that passes a low frequency component and cuts a high frequency noise.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, the present invention
An embodiment will be described with reference to the drawings. FIG. 1 shows Embodiment 1
FIG. 1 is a configuration diagram showing a control device for an induction motor according to the present invention. FIG.
Where 5 is the frequency command ω ^*Any voltage command value
V^*, And 6 is the output frequency of the subtractor 14.
Wave number command ω₀And voltage command value V of V / F controller 5^*By
Three-phase sine wave voltage reference V _U ^*, V_V ^*, V_W ^*Calculate
The phase voltage reference signal generator 7 is
Three-phase sine wave voltage reference V_U ^*, V_V ^*, V_W ^*Guided by
Three-phase voltage V applied to motor IM2_U, V_V, V_WOut
Powering inverter unit (ie, inverter), 2
Is the three-phase voltage V of the inverter unit 7_U, V_V, V_WTo
An induction motor (IM) whose operation is controlled more.

Reference numerals 10a, 10b, and 10c denote current detectors for detecting currents I _U , _IV , and I _W flowing from the inverter unit 7 to IM2, respectively, and 11 denotes a trigonometric function signal SINω _{0 according} to an output frequency command ω ₀ of the subtractor 14. t, COSω
₀ t trigonometric function signal generator for generating a, 12 a current detector 10a, 10b, 10c of the current I _U, I _V, trigonometric trigonometric function signal generator 11 I _W signal sin .omega ₀ t, CO
A 3φ / 2φ conversion unit that calculates a torque component current Iq of IM2 by performing 3φ / 2φ conversion at Sω ₀ t, and 13
A high-pass filter that extracts an unstable component of the torque component current, that is, a vibration component, from the torque component current Iq of the 2φ conversion unit 12, and a frequency correction component ω from the unstable component of the torque component current.
a frequency-correction-calculating section comprising a gain calculating section Ka for calculating _s ; a subtractor 14 for calculating an output frequency command ω ₀ from ω _s and the frequency command ω ^* of the frequency-correction calculating section 13;
Is a subtractor for subtracting the frequency correction ω _s from the frequency command ω ^*. The output of the subtractor 20 is input to the V / F controller 5 and reflected on the voltage command value V *.

The operation of FIG. 1 will be described. FIG. 2 is a waveform chart of the values of each part in FIG. When the speed ωr of the IM2 is oscillating as shown in FIG. 2A, a slip frequency as shown in FIG. 2B is generated. At this time, the torque component current Iq also has a vibration component shown in FIG. 2C according to the following equation (1). Iq ∝ slip frequency -------------- (1)

[0013] The only vibration component extracted using a high pass filter from the torque current Iq, and calculates a frequency correction component omega _s shown in FIG. 2 (d) using the following equation (2) relationship. ω _s振動 Vibration component of torque current Iq ------------- (2)

The subtractor 14 converts the output frequency command ω ₀ into the following (3) based on the frequency correction ω _s and the frequency command ω ^*.
Ω ₀ = ω ^* −ω _s -------------- (3) Input to the phase voltage reference signal generator 6. Similarly, the subtractor 20
To obtain ω ^* −ω _s and input to the V / F controller 5 to output a corrected voltage command value V ^* .

The output frequency command ω ₀ and the corrected voltage command value V ^* are input to the phase voltage reference signal generator 6 and operated by the phase voltage reference signal generator 6. The slip frequency (∝torque current Iq) of IM2 operated with the phase voltage reference signal calculated and output by the phase voltage reference signal generator 6 has no vibration component as shown in FIG. Thus, the operating characteristics of the induction motor can be obtained. The gain Ka and the time constant t of the high-pass filter in the frequency correction component calculating unit 13 are configured by a volume for an analog circuit, a memory or a self-erasable non-volatile memory for a digital circuit, and easily set values. It is needless to say that can be changed.

[0016] In addition, in the above, but it has entered the frequency command ω ^* to V / F control unit 5 is corrected by the frequency correction amount ω _s, V / F controller to directly enter the frequency command ω ^* 5
Of the V / F controller 5 may be obtained by compensating the temporary output with the frequency correction ω _s .

As in the first embodiment, the frequency correction ω _s
Therefore, both the voltage command value V ^* and the output frequency command ω ₀ are corrected, so that the magnetic flux of the induction motor IM2 is kept constant, and the torque that suppresses vibration is effectively compensated. be able to.

Embodiment 2 FIG. Also, as shown in FIG. 3, the V / F controller 5 converts the frequency correction ω _s into a voltage command value V
^* Stable operating characteristics can be obtained even if only ^* is reflected. This is because the applied voltage V _U of IM2, V _V, the torque current be changed V _W changes. By doing so, some of the components can be deleted, and the object can be achieved at low cost.

Embodiment 3 In the first and second embodiments, as shown in FIG. 4, a frequency command ω ^* or a frequency command ω ^{* is provided} between the frequency correction component calculation unit 13 and the 3φ / 2φ conversion unit 12.
By adding the weight function generator 30 that generates a weight corresponding to the output frequency command ω ₀ , a stable operation characteristic can be obtained near a desired operation frequency.

Embodiment 4 Further, Embodiments 1, 2, and
In 3, the filter configuration of the frequency correction component calculation unit 13 is a high-pass filter. However, the vibration component of the torque component current is extracted from the torque component current Iq of the 3φ / 2φ conversion unit 12, and the low frequency component is passed through to obtain the high frequency noise. , A more stable operation characteristic can be obtained without impairing the steady-state characteristic.

[0021]

As described above, according to the control apparatus for an induction motor of the present invention, a control apparatus for an induction motor that drives and controls an induction motor having no speed detector via an inverter is provided. A current detector for detecting an input current, a 3φ / 2φ converter for converting a current detected by the current detector to 3φ / 2φ and calculating a torque component current of the induction motor, from a torque component current calculated by the 3φ / 2φ converter A filter for extracting a vibration component of the torque component current, a frequency correction component calculation unit having a gain calculation unit for calculating a frequency correction component from the vibration component, and an output frequency command by subtracting the frequency correction component from an externally input frequency command. , A V / F controller that outputs a voltage command value corrected by the frequency correction based on the frequency command, and the voltage command value and the output frequency. Equipped with a phase voltage reference signal generator that outputs a three-phase voltage reference based on a number command and controls the output of the inverter, and controls so as to suppress vibration and operate stably, so a speed detector is used. And stable operation characteristics of the induction motor can be obtained. There is an effect that the system can be configured at low cost and stable operation characteristics of the induction motor can be obtained.

Also, in an induction motor control device for controlling an induction motor having no speed detector via an inverter, a current detector for detecting an input current of the induction motor, and a detection current of the current detector being 3φ 3φ / 2φ converter that calculates the current corresponding to the torque of the induction motor by converting the current to / 2φ,
A filter for extracting a vibration component of the torque component current from the torque component current calculated by the 3φ / 2φ converter, a frequency correction component calculation unit having a gain calculation unit for calculating a frequency correction component from the vibration component, and a frequency input from the outside V that outputs a voltage command value corrected by the frequency correction based on the command
/ F controller, and a phase voltage reference signal generator that outputs a three-phase voltage reference based on the voltage command value and controls the output of the inverter. Stable operating characteristics of the induction motor can be obtained without using a speed detector, and the system can be configured at lower cost.

In addition, the frequency correction portion calculation section has a 3φ / 2
Since there is a weighting function generator that weights the torque component current calculated by the φ converter in accordance with a frequency command or an output frequency command, stable operating characteristics can be obtained near a desired operating frequency.

Further, since the filter for extracting the vibration component of the torque component current is a band-pass filter that passes the low-frequency component and cuts the high-frequency noise, it is possible to obtain more stable operating characteristics without impairing the steady-state characteristics. it can.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a control device for an induction motor according to a first embodiment of the present invention.

FIG. 2 is a waveform chart of values of respective parts in FIG.

FIG. 3 is a configuration diagram showing a control device for an induction motor according to a second embodiment. It is.

FIG. 4 is a configuration diagram showing a main part of a control device for an induction motor according to a third embodiment.

FIG. 5 is a configuration diagram showing a main part of a control device for an induction motor according to a fourth embodiment.

FIG. 6 is a configuration diagram of a control system for stably operating a conventional induction motor.

[Explanation of symbols]

2 Induction motor 5 V / F controller 6 Phase voltage reference signal generator 7 Inverter 11 Trigonometric function signal generator 12 3φ / 2
φ conversion unit 13 Frequency correction minute operation unit 14 Subtractor 20 Subtractor 30 Weight function generator.

Continuation of front page (72) Inventor Yuji Kuramoto 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F-term (reference) 5H576 BB04 DD02 DD04 EE01 EE04 GG04 HB01 JJ17 JJ20 JJ25 JJ22 LL22

Claims (4)

[Claims] 1. A control device for an induction motor which drives and controls an induction motor having no speed detector via an inverter, wherein the current detector detects an input current of the induction motor, and the detected current of the current detector is 3φ. 3φ / 2φ converter that calculates the current corresponding to the torque of the induction motor by converting the signal to / 2φ.
A filter for extracting a vibration component of the torque component current from the torque component current calculated by the 2φ converter, a frequency correction component calculation unit having a gain calculation unit for calculating a frequency correction component from the vibration component, and a frequency command input from the outside. A subtracter for subtracting the frequency correction to calculate an output frequency command; a V / F controller for outputting a voltage command value corrected by the frequency correction based on the frequency command; and the voltage command value and the output frequency A control device for an induction motor, comprising: a phase voltage reference signal generator that outputs a three-phase voltage reference based on a command and controls an output of an inverter, and controls to stably operate by suppressing vibration. 2. A control device for an induction motor which drives and controls an induction motor having no speed detector via an inverter, wherein the current detector detects an input current of the induction motor, and the detected current of the current detector is 3φ. 3φ / 2φ converter that calculates the current corresponding to the torque of the induction motor by converting the signal to / 2φ.
A filter for extracting a vibration component of the torque component current from the torque component current calculated by the 2φ converter, a frequency correction component calculation unit having a gain calculation unit for calculating a frequency correction component from the vibration component, and a frequency command input from the outside. A V / F controller that outputs a voltage command value corrected by the frequency correction based on the voltage command value, and a phase voltage reference signal generator that outputs a three-phase voltage reference based on the voltage command value and controls the output of the inverter. , A control device for an induction motor that controls vibration so as to operate stably. 3. The frequency correction component calculating section includes a weight function generator for weighting the torque component current calculated by the 3φ / 2φ converter in accordance with a frequency command or an output frequency command. 2. The control device for an induction motor according to claim 2. 4. The induction motor according to claim 1, wherein the filter that extracts a vibration component of the torque component current is a band-pass filter that passes a low-frequency component and cuts a high-frequency noise. Control device.