Recent years have seen significant reductions in the commercial viability of UK wind farm development as a consequence of factors such as limited availability of turbines, increases in metal prices, reduced availability of skilled support for construction operations and grid access constraints. Despite this, the excellent wind resource and shallow waters around the UK ensure that offshore development is seen by government and the renewables industry as the most significant opportunity to realise very ambitious renewable energy targets and aspirations.

Nowadays, power electronics is an essential technology for enabling variable speed operation of wind turbines with increased energy capture and reduced mechanical stress. The commonly used doubly-fed induction generator only needs a small rated converter to enable variable speed operation and has a correspondingly low cost. On the other hand, permanent magnet (PM) generators have advantages such as no slip rings, high efficiency and the possibility of gearless operation. Their drawback is the need for a large power electronics converter, as the full power must be converted into voltage of fixed frequency suitable for the connection to the grid. This drawback motivates the search for new configurations with reduced losses, costs and space requirements. In this article, a new configuration using a variable series capacitor is investigated. The configuration shows simple control, low losses and a reduced need for semiconductor rating, and thus contributes to the technology shift towards permanent magnet generator solutions.

Enercon develops and produces gearless wind power turbines that are a benchmark for the market in terms of power, reliability and lifespan. Therefore, research and development at Enercon determines the level of innovation. Enercon has chosen Moeller's XC100-FC modular programmable logic controller (PLC) with a fibre-optic CANopen interface for controlling and monitoring its aviation beacon system. This article describes first the controls needed in the wind turbines and then how the modular PLC from Moeller is integrated into such systems.

The Wind Power Drive Train Package

Combining a permanent magnet (PM) generator with a power converter in a wind power drive train is simple, but nobody integrates them into a totally optimised package as The Switch does. The development of magnetic materials and power switches has made the combination of a PM generator and a full-power converter a very competitive solution for the next-generation wind power systems.

By Jussi Vanhanen, Marketing Manager, The Switch, Finland