Fault ride-through (FRT) is required for large wind farms in most power systems. Fixed speed wind turbines (FSWTs) are a diminishing but significant sector in the fast-growing wind turbine (WT) market. State-of-art techniques applied to meet grid requirements for FSWT wind farms are blade pitching and dynamic reactive power compensation (RPC). Blade pitching is constrained by the onerous mechanical loads imposed on a wind turbine during rapid power restoration. Dynamic RPC is constrained by its high capital cost. These present technologies can therefore be limiting, especially when connecting to smaller power systems. A novel alternative technology is proposed that inserts series resistance into the generation circuit. The series dynamic braking resistor (SDBR) dissipates active power and boosts generator voltage, potentially displacing the need for pitch control and dynamic RPC. This paper uses a representative wind farm model to study the beneficial effect of SDBR compared to dynamic RPC. This is achieved by quasi-steady-state characterization and transient FRT stability simulations. The analysis shows that SDBR can substantially improve the FRT performance of a FSWT wind farm. It also shows that a small resistance, inserted for less than one second, can displace a substantial capacity of dynamic RPC.

Abstract-The archimedes wave swing (AWS) is a system that converts ocean wave energy into electric energy. The goal of the research described in this paper is to identify the most suitable generator type for this application. Of the conventional generator types, the three-phase permanent-magnet synchronous generator with iron in both stator and translator is most suitable, because it is cheaper and more efficient than the induction generator, the switched reluctance generator, and the permanent-magnet (PM) generator with an air-gap winding. The paper also proposes a new transverse-flux PM (TFPM) generator topology that could be suitable for this application. This new double-sided moving-iron TFPM generator has flux concentrators, magnets, and conductors on the stator, while the translator only consists of iron.Index Terms-Direct-drive generator, linear machine, permanent-magnet (PM) machine, transverse flux machine, wave energy.

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