Communication-free Centralized Power Conversion of Wind Turbine Clusters and the Dynamic Low Frequency Wind Power System

Offshore wind power faces significant challenges in balancing cost and reliability, while most existing commercial or emerging technical solutions struggle to address both aspects simultaneously. The integration of wind farm centralized power conversion (CPC) technology with flexible low-frequency transmission presents a promising approach. This combined solution holds potential to minimize offshore power electronic devices, thereby reducing costs and enhancing reliability, though it first requires resolving the critical challenge of communication-free long-distance CPC. This paper begins by tracing the origin of power tracking control in variable-speed constant-frequency (VSCF) wind turbines. Analytical findings reveal that the maximum power point tracking (MPPT) control widely adopted in commercial turbines fundamentally operates as a model-based, power imbalance-driven rotational speed-wind speed progressive follow-up system, rather than a classical closed-loop feedback system. Such control methodology proves particularly advantageous for inherently huge-inertia wind turbines in achieving the comprehensive objectives of load reduction, power smoothing, and tracking efficiency. Building on this foundation, the study proposes a communication-free centralized power conversion (CPC) principle based on active power-frequency (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P</i>-<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i>) progressive follow-up control, accompanied by communication-independent compensation control and technical feasibility analyses. Furthermore, a flexible dynamic low-frequency wind power system (DLFWPS) is developed, incorporating multi-perspective suitability evaluations of various generator types. Through comprehensive simulations and experimental validation, the feasibility and superiority of both the communication-free CPC principle and the DLFWPS are conclusively demonstrated. The proposed system achieves comparable power production to conventional VSCF wind farms while exhibiting enhanced cost-effectiveness, grid frequency support and operational reliability.