Modeling and Control of a Continuously Variable Planetary Transmission for a Small Wind Turbine Drivetrain

This paper presents the modeling and control of a Continuously Variable Planetary (CVP) transmission in a wind turbine system. The primary purpose of this paper is to evaluate its effectiveness for mechanically decoupling the variable speed turbine rotor from the grid tied induction generator. It is expected that a CVP controlled wind turbine can take advantage of the grid tied induction generator without the use of an inverter, while optimizing the blade speed aerodynamically. This system also expands its operating range making it possible to track the optimal tip speed ratio over a wider wind speed range, which allows higher power to be captured from the wind. System characteristics have been studied by simulating an 8kW horizontal axis wind turbine in a MatLab/Simulink® environment. Experimental results have been included to verify the model of the system. Analyses conducted show that the continuously variable transmissions are potential candidates for small wind turbine applications.