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Asynchronous motor restart frequency sweep method and device

An asynchronous motor, restarting technology, used in motor control, starter parts, motor generator control and other directions, can solve the problem of inverter overcurrent, improve accuracy, reduce the step size of frequency search, and prevent overcurrent. flow effect

Active Publication Date: 2016-08-10
CSR ZHUZHOU ELECTRIC LOCOMOTIVE RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method uses the method of controlling the frequency to control the current, which is still easy to cause the inverter to over-current

Method used

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  • Asynchronous motor restart frequency sweep method and device
  • Asynchronous motor restart frequency sweep method and device
  • Asynchronous motor restart frequency sweep method and device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0053] Embodiment 1 of the present invention provides a frequency sweeping method when restarting an asynchronous motor, as shown in the attached figure 1 Shown is a flow chart of a frequency sweep method when an asynchronous motor is restarted disclosed in Embodiment 1 of the present invention, the method includes:

[0054] S101: Establish a current amplitude closed-loop control, and conduct a two-way full-frequency search on the stator;

[0055] S102: During the two-way full-frequency search process, compare the actual output voltage value with the N voltage comparison thresholds in the voltage comparison threshold group from small to large one by one. During the one-to-one comparison process, when the actual output voltage value When it is greater than the current compared voltage comparison threshold, then reduce the current frequency search step size, otherwise keep the corresponding frequency search step size;

[0056] Wherein, the maximum voltage comparison threshold i...

Embodiment 2

[0060] Based on the first embodiment of the present invention to provide a frequency sweep method when the asynchronous motor is restarted, as shown in the attached figure 2 As shown, in the technical solution disclosed in Embodiment 2 of the present invention, when the active current of the asynchronous motor is zero, if the maximum voltage comparison threshold is less than 95% of the actual output voltage value or greater than the actual output voltage value 105%, i.e. in the case where the maximum voltage comparison threshold is unreasonable, also includes:

[0061] S201: During the two-way frequency search process, when the active current is zero, determine the actual output voltage value, and select a voltage within 5% smaller than the actual output voltage value as a reference voltage comparison threshold;

[0062] S202: Based on the reference voltage comparison threshold, correct the voltage-frequency characteristic slope according to the voltage-frequency characterist...

Embodiment 3

[0070] Based on the above-mentioned method for sweeping the frequency of an asynchronous motor during restart provided by Embodiment 1 of the present invention, the specific process of step S102 is correspondingly disclosed in the technical solution disclosed in Embodiment 3 of the present invention, including:

[0071] During the one-to-one comparison, when the actual output voltage value is greater than M 1 times the maximum voltage comparison threshold, the initial frequency search step size S 0 reduced to S 1 ; When the actual output voltage value is greater than M 2 times the maximum voltage comparison threshold, then the S 1 Reduced to S on the basis of 2 ;Continue to compare, when the actual output voltage value is greater than M i When times the maximum voltage comparison threshold, where 3≤i≤N-1, then the previous frequency search step S i-1 Reduced to S on the basis of i ; among them, S 0 , S 1 ......S i-1 , S i ......S N-1 The value of is a positive integ...

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Abstract

The application discloses an asynchronous motor restart frequency sweep method and device. The method comprises the following steps: current amplitude closed loop control is established; when a stator is subjected to bidirectional full frequency searching operation, voltage values that are actually output are compared with N voltage comparison threshold values in a voltage comparison threshold value group from small to large in a one by one manner, a maximum voltage comparison threshold value is a product of a voltage frequency characteristic gradient and a frequency value in search processes, first N-1 voltage comparison values have maximum voltage comparison threshold values which are orderly M1 times to MN-1 times as much as of the first N-1 voltage comparison values, N is a positive integer greater than 1, and M1 to MN-1 are orderly positive numbers that orderly increase and are less than 1; when the voltage values that are actually output are greater than the voltage comparison threshold values being compared, step length of current frequency search is reduced, and otherwise the step length of current frequency search is maintained; when the voltage values that are actually output are not smaller than the maximum voltage comparison threshold values, that searched frequency is rotor synchronization frequency is determined, a frequency converter can be prevented from overflowing, and an aim of frequency sweep acceleration can be attained.

Description

technical field [0001] The present invention relates to the technical field of asynchronous motors, in particular to a frequency sweep method and device for restarting an asynchronous motor. Background technique [0002] At present, in the industry, it is often encountered that the asynchronous motor in the free rotation state is restarted. At this time, the rotor of the asynchronous motor may still be in a rotating state. For example, a fan with a relatively small moment of inertia may be rotated by natural wind. ; Locomotives, subways, and bullet trains are in a state of idling or ramp sliding; ship propellers rotate freely under the action of water flow, etc. However, because the current real speed of the asynchronous motor cannot be known when the asynchronous motor is restarted, if the rotor magnetic field is still running at a certain frequency, if the given stator frequency is too different from the rotor magnetic field frequency, there will be a gap in the motor oper...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02P1/02
CPCH02P1/022H02P1/029H02P2207/01
Inventor 刘可安尚敬梅文庆胡仙刘勇甘韦韦贾岩
Owner CSR ZHUZHOU ELECTRIC LOCOMOTIVE RES INST
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