Supplementary Damping Controllers Design in VSC HVDC Systems and Wind Farms to Improve Stability and Energy Conversion in Wind Turbine Using Proposed Genetic-Bat Algorithm

Connecting wind turbines to power networks without adversely affecting system stability is one of the most important future challenges to expand wind farms. In this paper, to improve the power network stability, damping the oscillations caused by torsional modes and increasing the energy conversion efficiency of wind turbines, a new control strategy was proposed for the active power control loop of wind turbines as well as HVDC transmission systems. First, the nonlinear speed-power curve of the wind turbine was shown to be effective in damping coefficients of torsional modes, energy conversion efficiency and the stability of the wind turbine. Accordingly, the use of wind turbine stabilizer in the wind turbine power control loop was proposed. Since the wind power plant is effective in the flow of the active-reactive power components, the use of supplementary damping controllers in the rectifier of VSC HVDC system was proposed to improve the voltage profile and the dynamic stability of the power network. The fractional order PID controllers were used in the proposed control strategy whose coefficients were adjusted using the proposed genetic-bat algorithm. In this algorithm, in order to avoid the rapid convergence of bats to local extremes and the optimal development of the search space, two operators of genetic algorithms, the dynamic mutation based on probabilities and the crossover were used. The simulation results showed that under the proposed control strategy, the stability of the system and the voltage profile in the network were significantly improved.