Loss and Rating Considerations of a Wind Energy Conversion System with Reactive Compensation by Magnetic Energy Recovery Switch (MERS)

Electrical conversion system for permanent magnet wind generators is challenging due to the large rating of power electronics devices needed and the associated costs. Additionally, due to the large inductance present in the generator (synchronous reactance), voltage drops results with resistive load and the generator output power is limited. A solution utilizing an active series compensation device called magnetic energy recovery switch (MERS) for cancelling the voltage drop across the synchronous reactance is investigated. MERS is a simple configuration with low switching losses. Due to the special characteristics of the configuration, a new IGBT with low on-state voltage has been applied. The performance of the configuration has been confirmed with experiments on a 50 kW multi-pole permanent magnet generator. Numerical investigations on large scale system indicate potential for loss reductions and rating reduction compared to using a conventional active rectifier solution.