Maximum power point tracking method for wind power generation system based on Boost convertor

Abstract

The invention provides a maximum power point tracking method for a wind power generation system based on a Boost convertor. The method concretely includes the following steps that a, a system is initialized, a tracking error is set, input voltages and input currents of the convertor before and after a sampling period are measured, and the difference delta P between the power before the sampling period and the power after the sampling period is calculated; b, the difference delta D between the duty ratios of the convertor before and after sampling is calculated; c, if delta P is larger than zero, the duty ratio is increased by a tracking step size variable quantity K, and if delta P is smaller than zero, the duty ratio is reduced by K; d, the quotient of delta P to delta D is calculated, and if an end condition is met, the system reaches the maximum power point; if the end condition is not met, the step a is executed, and the steps are repeated until the end condition is met. According to the method, wind speed or fan rotating speed is measured without depending on a mechanical measuring device, the tracking speed, stability and accuracy of the system are effectively improved by using a variable-step-size duty ratio disturbance tracking algorithm, and not only can output efficiency and electric energy quality be improved, but also complexity and cost of the system are reduced.

Description

technical field [0001] The invention relates to the technical field of automatic control of wind power generation, and relates to a method for tracking the maximum power point of a wind power generation system based on a Boost converter. Background technique [0002] Today, when sustainable development is advocated, wind energy, as a clean and renewable energy source, has received extensive attention. China has abundant wind energy resources, the total reserves of wind energy resources are about 160,000 MW, but wind energy has the characteristics of low energy density, randomness, and instability. In order to make full use of wind energy at different wind speeds and maximize the conversion of wind power generation systems To improve efficiency, measures must be taken to control the output power of the generator to ensure that the wind turbine always works at the maximum power point and maximize the utilization of wind energy. [0003] At present, the conventional ma...

AI Technical Summary

Problems solved by technology

These three methods have their own shortcomings: the tip speed ratio method needs to use mechanical sensors to measure the wind speed and the speed of the wind rotor, and also needs to know the inherent tip speed ratio curve of the wind turbine

The first two increase the actual cost of the system, and the actual curve of the fan characteristic curve will deviate from the original curve after the fan is used for a long time, making the wind energy MPPT tracking inaccurate

The hill-climbing search method does not need to measure the wind speed or speed, nor does it need to know the specific power characteristics of the wind turbine. It uses a fixed speed disturbance to maximize the wind energy capture of the wind turbine. However, this method uses a fixed disturbance step during tracking, and the disturbance step is too small , the response speed is slow, which reduces the rapidity of tracking; when the disturbance step is too large, the power oscillates near the maximum power point, resulting in a large difference between the tracked maximum power point and the actual value, which reduces the wind energy conversion efficiency

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