Permanent magnet motor voltage adaptive control system and method

Abstract

The invention provides a permanent magnet motor voltage adaptive control system and method. The system comprises a control device, three groups of three-phase power supplies, a three-phase transformerand a permanent magnet motor. A secondary coil of the three-phase transformer is connected with the permanent magnet motor through a relay and a control switch in the control device to control operation of the permanent magnet motor. The double-winding compensation transformer is adopted, forward and reverse series connection is carried out on windings to achieve multi-gear voltage, the remarkable advantages of being small in configuration capacity, small in operation loss, free of any harmonic wave and the like are achieved, and the control device achieves the operation mode of automatic detection and automatic control. The control device is used for calculating and processing various input data of the permanent magnet motor; and the current operation state of the permanent magnet motoris diagnosed according to the calculation result, the output voltage is automatically adjusted, automatic monitoring, automatic tracking and automatic regulation are sequentially realized, the optimaloperation voltage is provided for the permanent magnet motor, and the permanent magnet motor of the oil pumping unit is always in an efficient and economic operation state.

Description

technical field [0001] The invention relates to the technical field of permanent magnet motors, in particular to a permanent magnet motor voltage adaptive control system and method. Background technique [0002] The permanent magnet motor has the advantages of high efficiency and good power saving effect, and theoretically has a high power factor approximately equal to 1. At present, it has been rapidly popularized and applied on pumping units in oil fields. Compared with the three-phase asynchronous motors, although the typical engineering test results of the vigorously promoted permanent magnet motors are very encouraging, the large-scale tracking test found that more than half of the permanent magnet motors operate with a power factor below 0.5, and the energy consumption is similar to that of asynchronous motors. near. The power factor of the permanent magnet motor is close to 1, which is an important basis for replacing the asynchronous motor for energy-saving transfo...

AI Technical Summary

Problems solved by technology

Compared with three-phase asynchronous motors, although the typical engineering test results of the vigorously promoted permanent magnet motors are very encouraging, large-scale tracking tests have found that more than half of the permanent magnet motors operate with a power factor below 0.5, and the energy consumption is similar to that of asynchronous motors. near

The power factor of the permanent magnet motor is close to 1, which is an important basis for replacing the asynchronous motor for energy-saving transformation. If the power factor of the permanent magnet motor is too low, it will lose its replacement value and advantages

In addition, a long-term follow-up test found that if the mechanical structure of the pumping unit cannot be changed, the load rate of the motor cannot be increased, and the permanent magnet motor will demagnetize after long-term use, which further aggravates the severity of the problem

More than half of permanent magnet motors in oilfields cannot achieve the desired energy-saving effect, and their performance is close to that of asynchronous motors, forming an embarrassing dilemma of "tasteless to eat, but a pity to discard", which seriously limits the development of energy-saving industries in oilfields. It also caused a huge consumption and waste of human, material and financial resources.

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