Real-time maximized power generation of vertical axis wind turbines based on characteristic curves of power coefficients via fuzzy pulse width modulation load regulation

Highlights: • Real-time maximized power generation for a vertical axis wind turbine is presented. • Characteristic curve of a hybrid turbine with Savonius-Darrieus turbines is found. • Optimal tip speed ratio is proposed for a set point under varying wind conditions. • Fuzzy logic based PWM load regulation is implemented for maximum power generation. • Analysis and experiments of power generation from the hybrid turbine are conducted. -- Abstract: The efficiency of power generation is strongly dependent on wind speeds and rotational speeds of vertical axis wind turbines (VAWTs) over time. The efficiency is determined by the characteristic curves of power coefficients vs. tip speed ratios. In this work, the rotations of VAWTs can be tightly managed at the angular speed of the optimal tip speed ratio in order to yield the maximum mechanical work in a wide range of wind speeds, all the time. The maximized power generation of VAWTs is systematically obtained by a fuzzy pulse width modulation load regulation of power generation based characteristic curves of power coefficients. Regulated hybrid VAWTs are analytically and experimentally investigated to illustrate the significant improvement of power generation, compared with another traditional hybrid VAWT under varying low speed wind conditions. It is confirmed that the energy production of 16.50 Wh from the controlled VAWT is significantly higher (by 57.48%) than the 10.48 Wh from the uncontrolled VAWT in open field conditions during a testing day. In experimenting with the hybrid VAWT in a real working situation, the proposed methodology can be generalized for real-time implementation in maximizing the power generation of other VAWTs at a wind farm.