Controlling method and apparatus of discontinuous power supply combined with star angle converting for motor of pumping unit

Abstract

This invention discloses a control method for the discontinuous supply of a motor of a pumping unit combining star-angle transformation including: judging if the motor can be star-joint at heavy load, setting the cut off operation way to be a star-joint or an angle-joint, starting it with angle-joint, collecting the power curves of the motor to determine the cut-off position at the switched-on operation, switching the motor to the discontinuous supply operation in terms of said set cut-off operation ways at the cut-off time, testing the rotation speed of the motor to judge if it's necessary to switch-on, if not, continuing the test, if so, converting it to the switch-on operation at a proper position. This invention also discloses a control method for dynamic star-angle transformation and a control device for discontinuous supply combing star-angle transformation.

Description

technical field [0001] The invention relates to the control technology of the electric motor of the pumping unit, in particular to a control method and device for intermittent power supply of the electric motor of the pumping unit combined with star-angle conversion. Background technique [0002] Most of the pumping units currently used in oil fields are beam pumping units, which are a typical periodic load, and the maximum load and the minimum load differ greatly during operation. In order to overcome the static load moment in the starting process, when selecting and matching the motor capacity, a larger over-capacity motor is generally used for matching. However, when the pumping unit is running, the average load is only about 30% of the rated output power of the motor, and there is a serious waste of electric energy of "big horse-drawn carts". As the price of electricity continues to rise, in order to reduce the cost of oil production, it is necessary to study how to imp...

AI Technical Summary

Problems solved by technology

[0007] However, at the moment of the star angle change, the magnitude and direction of the motor magnetic flux will change, and the general switching operation will cause a great impact on the current and mechanical aspects. Therefore, for the case where the load rate often changes near the critical point, There will be certain problems with frequent star angle transformations

[0008] In addition, there is no technical solution that comprehensively considers the combination of the intermittent power supply control method and the energy-saving technology of star angle conversion in the prior art

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