Abstract:

In order to realize the generality of wind turbines hardware in the loop platform, a universal wind turbines hardware in the loop experiment platform is built to realize the optimal control of wind turbines. In view of the problem that direct drive wind turbines can affect the normal operation of direct drive wind turbines when the power grid voltage is unbalanced or asymmetrical, this study adopts the algorithm based on the decoupling of positive sequence current and negative sequence current to eliminate the negative sequence current and keep the constant output power. By inhibiting the double frequency fluctuation of the reactive power of the wind turbines when the fault occurs, the reference value of the active power and reactive power is 0, the amplitude of the double frequency fluctuation component of the grid reactive power is 0, and the purpose of eliminating the negative sequence current and making the output of the wind turbines stable is achieved. The simulation verification is carried out on the experimental platform. The experimental results show that the active power output of wind turbines remains unchanged and the grid-connection adaptability of wind turbines is significantly improved, which verifies the rationality and effectiveness of the method.

Key words: direct drive wind turbines, RTDS, unbalance voltage, phase-locked loop, UREP, universal platform, hardware-in-loop, optimal control