Maximum power control and optimization of switched reluctance generators for wind turbines

In recent years, renewable energy sources have gained importance due to depletion of the fossil fuels. Wind Power Plants (WPP) which are one of them have an important share in terms of energy production. To obtain maximum efficiency from these power plants, recent studies have focused on different types of the generators. Unlike conventional generators, using of Switched Reluctance Generators (SRG) has increased in variable speed wind turbines due to important advantages such as lower copper losses because of without windings in the rotors, simple structure, flexible control, good performance in a wide speed range. However, since SRGs work with switching logic, their torque production is fluctuating and optimum turn-on/turn-off angles of the phases must be determined to work as a generator. Determining right optimization techniques will increase the use of ARGs in WPPs. In this study, a wind energy conversion system using 4-phase 8/6-pole ARG is modeled by Matlab/Simulink. According to the generator speed, an optimization by designing a system that determines the optimum turn-on/turn-off angles and Maximum Power Point Tracking (MPPT) are realized. Besides, voltage control is provided by keeping the DC bus voltage at the system output constant at the desired value with the help of a chopper controlled unloader. The results obtained from the optimized model for variable wind speed conditions are compared with that of the unoptimized model. It is observed that the ARGs can work more stable with a proper optimization method and the power obtained from the system follows the maximum output power.