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Induction motor speed estimation method and power conversion device using same

A technology of power conversion device and induction motor, which is applied in the control of electromechanical transmission device, motor control, motor generator control, etc., can solve the problems of inability to perform stable speed control, insufficient torque, etc., achieve high-precision speed control characteristics, prevent Effects of insufficient torque

Active Publication Date: 2019-09-13
HITACHI IND EQUIP SYST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In this method, when the primary resistance value R1 changes with the winding temperature in the induction motor, the formula (1) used If there is an error between the setting value R1* and the primary resistance value R1, there will be an estimation error in the speed estimation value, so it cannot be performed. Stable speed control, in the low-speed range where the output voltage is low, the problem of insufficient torque occurs

Method used

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  • Induction motor speed estimation method and power conversion device using same
  • Induction motor speed estimation method and power conversion device using same
  • Induction motor speed estimation method and power conversion device using same

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Experimental program
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Embodiment 1

[0031] figure 1 is a configuration diagram of the power conversion device in this embodiment. figure 1 In the induction motor 1 driven by the power conversion device, the magnetic flux generated by the current of the magnetic flux axis component (d axis) and the current of the torque axis direction (q axis) orthogonal to the magnetic flux axis are generated. torque. Power converter 2 outputs and three-phase AC voltage command value V u * , V v * , V w * In direct proportion to the voltage value, the output voltage and output frequency of the induction motor 1 are adjusted. The DC power supply 2 a supplies a DC voltage to the power converter 2 . The current detector 3 outputs the three-phase AC current I of the induction motor 1 u , I v , I w The detection value of I uc , I vc , I wc . The current detector 3 can also detect phase currents of two of the three phases of the induction motor 1, such as the U phase and the W phase, depending on the AC condition (I u ...

Embodiment 2

[0118] In the first embodiment, the accuracy of the speed estimation value is improved in the low-speed section, but in the present embodiment, the method of improving the accuracy of the speed estimation value in the medium-high speed section will be described.

[0119] The structural diagram of the power conversion device in this embodiment is in figure 1 Since the structure is the same except for the speed estimation calculation unit 5, the drawings and descriptions thereof are omitted.

[0120] The speed estimation operation part 5' in this embodiment estimates the back electromotive force value of the t-axis according to formula (20), and outputs ω by dividing by the magnetic flux coefficient r ^^^ .

[0121] [mathematical formula 20]

[0122]

[0123] The voltage component ω included in the numerator term of formula (20) in the middle and high speed range 1 * L σ * I m * because I m * = 0, so even if L σ * There is an error in the setting of , and it is a...

Embodiment 3

[0128] In the first embodiment, the accuracy of the speed estimation value is improved in the low-speed section, but in this example, the method of switching the speed estimation value between the low-speed section and the medium-high speed section will be described.

[0129] The structural diagram of the power conversion device in this embodiment is in figure 1 Since it has the same structure except for the speed estimation calculation unit 5, its drawings and descriptions are omitted.

[0130] exist Figure 7 The structure of the speed estimation operation part 5'' in this embodiment is shown in . The speed estimation operation part 5''a is a calculation part of equation (16), and outputs the speed estimation value ω r ^^ , 5''b is the calculation part of formula (20), and the output speed estimation value ω r ^^^ . 5''c is the switching part of the speed estimation value, and the speed estimation value ω is selected in the low speed section r ^^ , select the speed e...

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Abstract

The present invention relates to the speed sensorless vector control of an induction motor and the purpose thereof is to provide a speed estimation method capable of preventing torque shortage causedby the coil temperature inside the induction motor and obtaining highly accurate speed control characteristics and to provide a power conversion device using the speed estimation method. In order to achieve the above purpose, a power conversion device for driving an induction motor by speed sensorless vector control has: a coordinate conversion unit for converting a command value or a detection value to control axes using a primary current direction and a direction delayed by 90 degrees from the primary current direction as a rotating coordinate system; and a speed estimation calculation unitfor calculating the speed estimation value of the induction motor on the basis of the command value or the detection value converted by the coordinate conversion unit. The power conversion device controls an output frequency value on the basis of the speed estimation value.

Description

technical field [0001] The present invention relates to speed sensorless vector control of an induction motor that does not use a speed sensor, and relates to a speed estimation method of an induction motor and a power conversion device using the same. Background technique [0002] There is a so-called speed sensorless vector control in which the speed of the induction motor is estimated without providing a speed sensor, and the speed of the induction motor is controlled based on the speed estimation value. As background art in this technical field, there is Japanese Unexamined Patent Publication No. 6-105580 (Patent Document 1). In Patent Document 1, a disturbance observer is installed to estimate the back electromotive force value of the q-axis, and divide it by the magnetic flux coefficient to calculate the speed estimation value ω according to the following formula (1). r ^ . [0003] [mathematical formula 1] [0004] [0005] Here, R 1 : primary resistance value...

Claims

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Application Information

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IPC IPC(8): H02P21/18H02P21/24H02P27/06
CPCH02M7/48H02P21/24H02P21/18H02P2207/01
Inventor 户张和明岩路善尚金子悟大桥敬典中村敦彦小沼雄作杉本卓也
Owner HITACHI IND EQUIP SYST CO LTD
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