Fuzzy Logic-based Digital Hydraulics Control of Blade Pitch Angle in Wind Turbines

Abstract

Abstract The pitch control system is generally employed in a wind turbine to mitigate load and maintain uniform power generation at above-rated wind speed regions. The hydraulic system has more power to weight ratio and so it is incorporated in the pitch system of large scale wind turbines. Some of the issues related to the usage of conventional valves in the Hydraulic Pitch System (HPS) are: internal leakage, throttling losses, high power loss, less fault-tolerant, requires high manufacturing tolerance, and more sensitive to contamination. To overcome these issues, digital hydraulics technology should be introduced as Digital Hydraulics Pitch System (DHPS). Commercially, Proportional Integral Derivative (PID) controller is used as a pitch controller but these controller performances don’t hold good when excessive disturbance or change in operating point occurs in the system. So, heuristic-based Fuzzy Logic Controller (FLC) is preferred which can surpass the PID problems. In this paper, a heuristic FLC based control strategy is proposed for a novel DHPS configuration to control the pitching action. The simulation model of DHPS is developed and system simulations are conducted. The comparative study on the effectiveness of FLC for DHPS and conventional valve controlled HPS is conducted.