Full range power control strategies for variable-speed fixed-pitch wind turbines

Abstract

In this paper, a new simple and effective full-range power control strategy for variable-speed fixed-pitch wind energy conversion system (WECS) was proposed. With this control strategy, not only the safe and stable operation of the WECS over full range of wind speed was guaranteed, but also the natural transition among maximum power point tracking (MPPT), constant rotational speed, and constant power operational regions was achieved. The operational principle of the proposed strategy was firstly analyzed, and then an experimental platform was established and the feasibility, merits and drawbacks were discussed according to the experimental results. Subsequently, a novel soft-stall power control strategy was further proposed within the whole wind velocity range. The operational principle and annual energy yield of the soft-stall strategy were carefully analyzed. It is found that the soft-stall control strategy can remarkably reduce the dynamic load, prolong the lifespan of WECS. What's more, experimental results of soft-stall control strategy indicate that the rated power of generator and power converters can be greatly reduced compared to the first control strategy. © 2012 Chin. Soc. for Elec. Eng.