Matrix converter-based PMSG proportional-integral resonance control method under unbalanced power grid

Abstract

The invention discloses a matrix converter-based PMSG proportional-integral resonance control method under an unbalanced power grid. The method can effectively realize control objectives of stator current balance and PMSG electromagnetic torque stability, has no positive and negative sequence separation link in a control loop, reduces the problems of time delay, a phase angle and a detection error of an amplitude value brought by a positive and negative sequence separation process, is simple and convenient to calculate, has good dynamic characteristics, and can realize rapid and precise control. A proportional-integral coefficient in the control method provided by the invention can directly adopt design parameters of a PI regulator under traditional balanced conditions, and has relatively strong adaptability. At the same time, the matrix converter-based PMSG proportional-integral resonance control method under the unbalanced power grid further verifies feasibility and scientificity of application of a matrix converter to a direct-driven type permanent magnet power generation technology, enables a matrix converter-based PMSG system to realize a good operation effect both in an ideal power grid and under unbalanced network voltage, and has very good research value and practical value.

Description

technical field [0001] The invention belongs to the technical field of wind power generation control, and in particular relates to a PMSG proportional integral resonance control method based on a matrix converter in an unbalanced power grid. Background technique [0002] With the deterioration of the living environment of human beings and the increasing shortage of global fossil energy, countries all over the world are vigorously developing various renewable energy sources. Wind energy is safe, clean, rich in resources and inexhaustible. It is the fastest growing and most promising green energy among renewable energy sources. Wind power generation is the main form of wind energy. Among them, the permanent magnet direct drive wind power system adopts the method of direct connection between the wind turbine and the permanent magnet synchronous generator (PMSG), cancels the speed-up gearbox, reduces system maintenance, and reduces operating costs. Noise, greatly improving the ...

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Problems solved by technology

[0005] Most of the current PMSG wind turbine control strategies are mainly designed for ideal grid conditions with constant grid voltage amplitude and frequency and continuous phase, but the actual grid is often not ideal, and grid faults often exist, especially asymmetric faults in the actual power system. It causes the stator current to be highly unbalanced, the electromagnetic torque pulsates, and the power transmitted to the grid oscillates

Therefore, the control strategy in the case of unbalanced grid voltage has become a research hotspot at home and abroad in recent years, but the current research results are mainly based on the control strategy under the dual PWM inverter excitation system. Since the matrix converter has no intermediate energy storage link, Unbalanced grid voltage, large disturbance and other abnormal working conditions will directly affect the motor side, which aggravates the difficulty of control. Therefore, it is necessary to study the PMSG control strategy based on the matrix converter under unbalanced grid voltage conditions.

[0006] At present, in the research on the operation control of direct-drive permanent magnet wind power generation technology in unbalanced grid, most of them are aimed at the control system based on AC-DC-AC dual PWM converters, and do not involve the control system based on matrix in unbalanced grid. The operation control of the PMSG of the converter

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