Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Induction motor drive unit, motor drive system, and elevating system

A technology of induction motor and driving device, applied in the field of lifting system, can solve the problem of unnecessary consideration of deceleration of induction motor or stop processing slip frequency and other problems

Active Publication Date: 2008-12-24
HITACHI IND EQUIP SYST CO LTD
View PDF1 Cites 15 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] However, in the technique of Patent Document 1, it is not considered to optimize the slip frequency which is the reference for the deceleration or stop processing of the induction motor.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Induction motor drive unit, motor drive system, and elevating system
  • Induction motor drive unit, motor drive system, and elevating system
  • Induction motor drive unit, motor drive system, and elevating system

Examples

Experimental program
Comparison scheme
Effect test

no. 1 Embodiment approach

[0026] As shown in Equation (1), when using lifting equipment such as a crane to hoist the cargo at an acceleration α, the required torque τm depends on the acceleration α and the weight m·g of the cargo (cargo). In addition, in formula (1), the cargo is hoisted by a pulley with radius r, J is the total moment of inertia including the motor or mechanical system (pulley, etc.), ω is the rotation speed of the motor, m is the mass of the cargo, and g is acceleration of gravity.

[0027] M·α·r=J·dω / dt=τm-m·g·r (1)

[0028] At this time, the maximum value of torque τm is determined by the capacity of the motor. When m·g·r is large, the acceleration α of formula (1) is negative or zero, and the cargo cannot be lifted. Furthermore, even if the acceleration α is positive, if the velocity change rate dω * / dt ratio (maximum torque τm max -m·g·r) / J is large, the motor cannot follow the instruction and the hoisting fails.

[0029] FIG. 1 is a configuration diagram of a motor drive sy...

no. 2 Embodiment approach

[0084] In the first embodiment, the occurrence of the maximum torque is detected based on the slip frequency ωs, but if figure 2 As shown, the determination that the slip frequency ωs exceeds ωsmax can also be determined based on the secondary side q-axis magnetic flux φ2q. As shown in FIG. 4 , the acceleration determination unit 5b of the second embodiment corresponds to the acceleration determination unit 5 ( FIG. 1 ), and includes a threshold calculation unit 42 and a comparison unit 43, and inputs the φq estimation calculation unit 40 as a q-axis magnetic flux calculation unit. and the output signal of the maximum torque generation φq calculation unit 41 as the maximum torque generation q-axis magnetic flux calculation unit.

[0085] A q-axis magnetic flux estimated value φ2q^ corresponding to ωs^ is calculated in the φq estimation calculation unit 40 , and a q-axis magnetic flux φ2qmax corresponding to ωsmax is calculated in the maximum torque generation φq calculation un...

no. 3 Embodiment approach

[0088] Differences between the third embodiment and the other embodiments will be described.

[0089] The acceleration determination unit 5c shown in FIG. 5 corresponds to the acceleration determination unit 5 (FIG. 1), but the q-axis magnetic flux estimation value φ2q^ may be calculated in the q-axis magnetic flux calculation unit, that is, the φq estimation calculation unit 40 instead. ωs^, in the maximum torque generation q-axis magnetic flux calculation unit 41 that is the maximum torque generation φq calculation unit, the q-axis magnetic flux φ2qmax corresponding to ωsmax is calculated.

[0090] The comparison unit 53 outputs a signal when φ2q^ is smaller than the output φ2qmaxTH of the threshold calculation unit 42 . The timer 54 outputs the time from the time when the above-mentioned signal was received. That is, when the state of 0>φ2qmaxTH>φ2q^ continues and the output of the timer 54 exceeds a predetermined threshold, the acceleration determination unit 5c determine...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The present invention provides an induction motor drive device (90), which includes a power inversion unit (15), for driving an induction motor (16); a slip frequency estimating unit (3), for estimating the slip frequency of the induction motor (16); a maximum torque generating slip frequency estimating unit (4), for estimating a maximum torque generating slip frequency for generating maximum torque of the induction motor (16); and an acceleration determination unit (5), for determining the acceleration possibility in the induction motor (16), wherein the acceleration impossibility is determined when the slip frequency exceeds the maximum torque generating slip frequency for the predetermined interval or the time integrating result exceeds a predetermined value. Thus, the motor torque is generated nearby an ideal maximum when the acceleration impossibility is determined.

Description

technical field [0001] The present invention relates to an induction motor driving device, a motor driving system, and a lifting system using them for driving and controlling variable speed operation of an induction motor. Background technique [0002] When using a lifting device such as a crane to raise goods, the following technology is required, that is, while preventing the excessive motor slip (すべり) (over-rotation) when the fixed acceleration rate of the induction motor is too fast relative to the load Differential rate), while preventing the falling of goods caused by load fluctuations caused by overload, load state, vibration, etc., thermal constant fluctuations of the motor, etc. In Patent Document 1, a rotation speed detector is used to obtain the slip frequency (subori cycle) of the induction motor from the rotation speed detection value and the motor input frequency (primary frequency), and when the slip frequency exceeds a predetermined value, the Decelerate, or...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): H02P27/06H02P21/00H02P27/04H02P21/22H02P23/07H02P23/16
CPCH02P21/08H02P23/08H02P25/22
Inventor 荒川阳一郎永田浩一郎富田浩之
Owner HITACHI IND EQUIP SYST CO LTD
Features
  • Generate Ideas
  • Intellectual Property
  • Life Sciences
  • Materials
  • Tech Scout
Why Patsnap Eureka
  • Unparalleled Data Quality
  • Higher Quality Content
  • 60% Fewer Hallucinations
Social media
Patsnap Eureka Blog
Learn More

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2025 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com