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A method to prevent low frequency overcurrent in asynchronous motor speed tracking

An asynchronous motor, low frequency technology, used in motor control, AC motor control, electrical components, etc.

Active Publication Date: 2022-07-05
WISDRI WUHAN AUTOMATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The invention discloses a method for solving the low-frequency overcurrent during the Vf control speed tracking process of an asynchronous motor in engineering practice, and avoids the occurrence of the overcurrent phenomenon by processing the current judgment threshold at the low frequency stage

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  • A method to prevent low frequency overcurrent in asynchronous motor speed tracking
  • A method to prevent low frequency overcurrent in asynchronous motor speed tracking
  • A method to prevent low frequency overcurrent in asynchronous motor speed tracking

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Embodiment Construction

[0017] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0018] like figure 1 Shown is a flow chart of the method of the present invention.

[0019] Step 1: Magnetic delay waiting. After this stage is completed, enter the target sweep current rising stage. The flow chart of the magnetic delay waiting method is as follows figure 2 shown.

[0020] Step 2: Process the target frequency sweep current rising stage, set the operating frequency to a fixed val...

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Abstract

The invention provides a method for preventing low frequency overcurrent in the speed tracking of an asynchronous motor. In the present invention, the operating frequency is set to a fixed value higher than the maximum operating frequency, the given output voltage is gradually increased according to a certain slope, and it is observed whether the output current is close to the target frequency sweeping current value, and the frequency sweeping stage is judged; The stage processing gradually reduces the given frequency according to a certain slope, and performs delay judgment processing to enter the excitation delay processing stage; in the low-frequency current threshold judgment processing, the current judgment thresholds of different frequency points are set; the given frequency is unchanged and passed The normal V / f curve obtains the normal target voltage value, and then the given voltage value is gradually changed to the target voltage value according to a certain slope. When it is completed, the delay processing is performed, and the delay is completed. The present invention uses the processing of the current judgment threshold value in the low frequency stage to avoid the occurrence of the overcurrent phenomenon and improve the stability of the system.

Description

technical field [0001] The invention belongs to the technical field of asynchronous motor control, and in particular relates to a method for preventing low-frequency overcurrent in the speed tracking of an asynchronous motor. Background technique [0002] For the motor that has been rotating at a certain speed before the controller is put into operation, when the controller is put in and running, if it is directly put into operation, it will often cause the problem of overcurrent due to the large difference between the given frequency and the actual running speed of the motor. The speed tracking restart function is to obtain the running speed of the motor through an appropriate method for the rotating motor, and then switch it into the normal control process after certain processing, but in the asynchronous motor Vf speed tracking process, The frequency judgment error is prone to occur in the low frequency stage, resulting in a large difference with the actual running speed ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02P27/04H02P29/024
CPCH02P27/047H02P29/027
Inventor 许小龙余红德王胜勇卢家斌
Owner WISDRI WUHAN AUTOMATION