This paper considers an offshore wind turbine modular power converter (ac/dc) with permanent magnet synchronous generator based on three stages: an ac-ac converter, a medium-frequency transformer, and a full-bridge diode rectifier with LC output filter. Six converter topologies are compared; three of them are based on back-to-back (B2B) topology: the conventional B2B with three-phase sinusoidal waveform, the B2B with three-phase squared waveform, and the B2B with single-phase squared waveform. The other solutions are based on matrix topologies: the direct matrix converter, the indirect matrix converter, and the reduced matrix converter (RMC). A systematic methodology and main component models are introduced to evaluate the power loss, volume, and mass of the wind energy conversion system for all considered topologies as a function of the medium-frequency transformer operational frequency and the number of modules parallel connected. The comparison involves a tradeoff study between total power losses, size and weight of 10 MW modular converters. It was found that when Metglas alloy 2605SA1 is the transformer core material, the RMC topology leaves the best tradeoff between the considered performance indicators with an extra benefit in reducing the semiconductor devices cost of the modular converter.

Linear Quadratic Gaussian (LQG) control methodology shows useful properties of good performance and robust-ness in controller design applied to wind turbine. Typically, in the design procedure LQG method is necessary to select weighting matrices in order to solve the Algebraic Riccati Equations and then get the matrices Kalman Filter gain and optimal state-feedback. In order to optimize a LQG control applied to Double-Fed Induction Generator in wind power system, a Genetic Algorithms (GA) adapted to get the best values of the element of weighting matrices is proposed in this paper. The performance indices ISE and ITSE are a good alternative to obtain the fitness function to design LQG controllers with GA. The simulation results show the high effectiveness of this optimal design method

This paper introduces an analytical design methodology for Battery Energy Storage Systems (BESS) in hybrid marine vessels. Models for performance evaluation of a BESS composed by a battery array, an AC/DC power converter and a transformer are introduced and used to evaluate the potential fuel savings, projected lifetime and cost-benefit of BESS installation on a considered hybrid marine power system. By parametric sweep of free design parameters, the trade-off between different performance indices is analyzed and the optimal sizing (energy capacity and rated power) of the BESS can be obtained.

Inductors are one of the largest and heaviest components of the DC-DC converter in medium/high power applications. As volume/weight of the converter becomes more important, high frequency is considered in the design of the converter and inductors with low inductance and high currents are required. Air-core inductors can be considered as good alternative, since they are not subject to saturation problems and may provide a reduction on total weight and losses of the converter if an appropriated design is performed. This paper presents an analysis of air-core inductors for DC/DC converters. First, a simplified inductor design is proposed to optimize the power losses by using litz wire winding. Then, results from the proposed design methology are compared with commercial iron-core inductors byusing metaparameterisation approach. A comparative analysis is performed between commercial iron-core inductors and air-core inductors regarding power losses, volume and weight for a bidirectional DC-DC converter. Because the number of parameter that influence the selection of the inductance in a DC-DC converter, then the comparison is done by use desicion chart, which help to define when a type of inductor is better than the other. Air-core inductor will left more benefit for power rating higher than 1MW.

This paper presents a meta-parameterized approach for the evaluation of Power Switch Modules (PSMs) in power converters. General models and parameters for the evaluation of power losses and volume of a PSM are presented. Then, meta-parameterization is performed for two semiconductor devices that have been successfully commercialized for low/medium power converters, Si-IGBTs, and SiC-MOSFETs. A comparative analysis based on the efficiency and power density of the considered technologies is presented. A bidirectional non-isolated DC-DC converter topology is considered as application example in order to show how meta-parameters can be used in comparative studies to optimize device selection.