Modeling And MPPT Control Strategy Study Of Small Scale Direct-drive Permanent Magnet Wind Power System

Because of its abundant, clean, renewable and other characteristics, wind power generation has become one of the main directions of research on renewable generation. Small scale wind turbine, with its low capital cost, is widely used in remote mountainous areas and islands that power grid can’t give support, Therefore, it has important practical significance to study the characteristics and control strategy of small wind power generation systems.In order to make high-efficiency use of wind power, it’s necessary to study the maximum power point tracking(MPPT) control strategy. At present, most control strategies about wind turbine MPPT need to extract information about wind speed. It’s difficult to accurately measure the wind speed with strong randomness and volatility. Moreover, mechanical sensors not only increase the cost but also reduce the reliability of the overall system. Therefore, this paper uses the support vector machine which is optimized by the firefly algorithm to establish a high-precision estimation model of wind speed by measuring the fan speed and power.For studying the wind turbine characteristics and verifying the control strategy, the model of the wind turbine and control system is built with MATLAB. Meanwhile, constant step-size P&O method, variable step-size P&O method and hybrid power MPPT control strategy proposed in this paper are simulated. Results show that the maximum power point tracking method proposed in this paper can effectively shorten the time to find the maximum point, improve the accuracy and reduce the power loss.At the same time, the MPPT control strategy proposed in this paper is implemented in hardware, which proved the feasibility of this method.