Voltage unbalanced mathematical model-based control strategy for brushless double-feed motor grid-side converter

Abstract

The invention relates to a voltage unbalanced mathematical model-based control strategy for a brushless double-feed motor grid-side converter. Unbalanced voltage vectors are decomposed into balanced positive sequence components, negative sequence components and zero sequence components by utilizing a symmetrical component method; a mathematical model of the grid-side converter is created when the voltage is unbalanced; and the problems of coupling terms and external disturbance existing in the grid-side converter are observed and compensated by utilizing an expansion state observer and a self anti-interference control theory. A nonlinear control method designed in the invention can inhibit the harmonic wave problem of the grid-side converter under the voltage unbalanced condition very well, and has the advantages of strong anti-interference capability, favorable robustness, and the like.

Description

【Technical field】 [0001] The invention relates to a control strategy of a brushless doubly-fed motor grid-side converter based on a mathematical model of voltage unbalance, and belongs to the cross technical fields of new energy utilization and control, electric engineering and power electronics. 【Background technique】 [0002] At present, energy consumption is increasing rapidly around the world, and the consumption of fossil fuel energy will still occupy a dominant position, which will cause many problems such as environment, health, economy and energy security. Over the past 20 years, renewable energy technologies have achieved great breakthroughs in reliability and performance while successfully reducing costs. Among them, wind energy, as a renewable, non-polluting and clean energy, has been paid more and more attention by human beings. [0003] According to the current research situation, the variable-speed constant-frequency wind power generation technology is the mos...

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Problems solved by technology

[0005] At present, there are many control strategies for converters, including static PI control, fuzzy PID control, direct power control, current hysteresis control, deadbeat control, control based on Lyapunov method, predictive control, nonlinear control, neural network control, fuzzy Sliding mode variable structure control, based on single-cycle control, etc., but looking at the above-mentioned control methods, the mathematical models used in the control strategies are basically derived under the condition of grid balance, but in the actual three-phase In the power grid, the grid voltage is often unbalanced due to various reasons, and the control strategy designed under the condition of grid voltage balance often forms harmonics with low frequency and high amplitude, which seriously affects the operation of the grid-side converter performance

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