Study On The Laboratory Platform For VSCF-DFIG Wind Power Generation

With the pressing situation of fossil fuel exhaustion and environmental pollution, clean and renewable energy resources, among them the wind energy is of prominent importance, are gaining more and more attention. Doubly-fed induction generator (DFIG) is an attractive and booming approach that provides the ability of variable speed constant frequency wind power generation with low cost and high efficiency. The dissertation is devoted to an in-depth study on some key problems around wind aerodynamics, wind turbine, power electronics, control strategy, and system integration, especially to the design and construction of a laboratory platform dedicated to the research and development of DFIG.1. The DFIG in a variable speed constant frequency grid-connected generation system is studied to get mathematical models based on electro-magnetic analysis, and various strategies, such as flux-oriented vector control for DFIG speed/power control when grid-disconnected or -connected, are deduced and simulated, the control strategy of no load cutting of variable speed constant frequency doubly fed induction generator with grid voltage feedback is proposed in this paper, the control strategy realizes soft grid-connected by resulation,2. A fuzzy-PI hybrid control is developed and proposed for the outer loop control displaying merits in stability and robustness,which realizes the decoupled control of the active power and reactive power for stator output.3. The analysis with the usage of switching function is applied to three-phase voltage source converter. The current control with fixed switching frequency and grid voltage forward-fed is used and simulated under Matlab/Simulink. the resulation verifies the correctness and feasibility of the three-phase voltage source inverter with this control strategy as power supply of Variable speed constant frequency doubly fed induction generator.4. Four wind speed models that may be composed to emulate real wind process are established for base wind, gust, ramp wind and noisy. Based on Labview, the wind spectra generation is effectively and satisfactorily implemented.5. A control strategy for maximum power point tracking (MPPT) that avoids the contradiction to speed control is developed, which overcomes the disorder of the wind speed.6. A laboratory simulation/emulation platform, that consists of an inverter-driven squirrel-cage motor to emulate wind turbine, a set of DC linked dual back-to-back PWM voltage-source converters, dual TMS320LF2407 based controllers, etc. is designed andimplemented for the project "1 lOkw VSCF doubly fed induction generator wind power system". A good number of laboratory items performed on this platform made tests, verification, as well as support and contribution to the completion of the dissertation.