In this paper, the principle of modularity is used to derive the different multilevel voltage and current source converter topologies. The paper is primarily focused on high-power applications and specifically on high-voltage dc systems. The derived converter cells are treated as building blocks and are contributing to the modularity of the system. By combining the different building blocks, i.e., the converter cells, a variety of voltage and current source modular multilevel converter topologies are derived and thoroughly discussed. Furthermore, by applying the modularity principle at the system level, various types of high-power converters are introduced. The modularity of the multilevel converters is studied in depth, and the challenges as well as the opportunities for high-power applications are illustrated.

Modular Multilevel Converters for HVDC Applications: Review on Converter Cells and Functionalities

Soft magnetic materials are key to the efficient operation of the next generation of power electronics and electrical machines (motors and generators). Many new materials have been introduced since Michael Faraday's discovery of magnetic induction, when iron was the only option. However, as wide bandgap semiconductor devices become more common in both power electronics and motor controllers, there is an urgent need to further improve soft magnetic materials. These improvements will be necessary to realize the full potential in efficiency, size, weight, and power of high-frequency power electronics and high-rotational speed electrical machines. Here we provide an introduction to the field of soft magnetic materials and their implementation in power electronics and electrical machines. Additionally, we review the most promising choices available today and describe emerging approaches to create even better soft magnetic materials.

http://science.sciencemag.org/content/sci/362/6413/eaao0195.full.pdf

Soft magnetic materials for a sustainable and electrified world

A wide range of microelectromechanical systems (MEMSs) and devices are actuated using electrostatic forces. Multiphysics modeling is required, since coupling among different fields such as solid and fluid mechanics, thermomechanics and electromagnetism is involved. This work presents an overview of models for electrostatically actuated MEMSs. Three-dimensional nonlinear formulations for the coupled electromechanical fluid–structure interaction problem are outlined. Simplified reduced-order models are illustrated along with assumptions that define their range of applicability. Theoretical, numerical and experimental works are classified according to the mechanical model used in the analysis.

https://iopscience.iop.org/article/10.1088/0964-1726/16/6/R01/pdf

Review of modeling electrostatically actuated microelectromechanical systems

Field responsive materials: photo-, electro-, magnetic- and ultrasound-sensitive polymers

Global electricity demands are increasing at rapid pace Energy supply, their usage and technologies involved need to be more economical, environment friendly and socially sustainable Efforts are being done all over the globe to reduce this greenhouse effect; and renewable energy technologies to combat climate changes, which require extensive changes to the current electricity generation and distribution systems To meet this goal, it is required to optimize the grid operations and available resources to meet the ever increasing energy demands in an efficient, effective and environment sustainable way It has been found that smart grid technologies have not been so popular due to some obstacles that are hindering its maturation and rapid deployment An attempt has been made to identify and analyze the barriers to implement smart grid technologies adoption Twelve relevant barriers towards implementation of smart grid technologies have been identified from extensive literature review and duly validated with experts׳ (from academia and industry) opinions Also, valuable experts׳ opinions have been utilized to identify contextual relationships among these important barriers and a hierarchical model has been developed based on Interpretive Structural Modeling methodology Matrice d׳Impacts Croises-Multipication Applique´ an Classment (MICMAC) analysis has also been used to: classify the barriers based upon dependence and driving power; and validate developed ISM based model “Lack of Regulatory Framework” barrier has been identified as driver or independent level barrier ie most important bottom level barrier hindering adoption of smart grid technologies The developed structured model will help to understand interrelationships and interdependencies among the identified barriers to implement smart grid technologies Different solutions for handling these identified barriers have also been suggested in the paper Organizations involved in power generation and distribution may be benefited by understanding of these barriers, their interactions and suggested mitigation solutions towards effective adoption of smart grid technologies

Adoption of smart grid technologies: An analysis of interactions among barriers

http://documents.irevues.inist.fr/bitstream/handle/2042/6561/LCB80.pdf;sequence=1

Liquid cooling of bright LEDs for automotive applications

With the advances in the technology of materials based on GaN, high brightness white light emitting diodes (LEDs) have flourished over the past few years and have shown to be very promising in many new illumination applications such as outdoor illumination, task and decorative lighting as well as aircraft and automobile illuminations. The objective of this paper is to investigate an active liquid cooling solution of such LEDs in an application of automotive headlights. The thermal design from device to board to system level has been carried out in this research. Air cooling and passive liquid cooling methods are investigated and excluded as unsuitable, and therefore an active liquid cooling solution is selected. Several configurations of the active liquid cooling system are studied and optimisation work has been carried out to find an optimum thermal performance.

Liquid Cooling of Bright LEDs for Automotive Applications

Power electronics is a key technology for the efficient conversion, control, and conditioning of electric energy from the source to the load. In this paper, the potential of power electronics for energy savings in four major application fields, buildings and lighting, power supplies, smart electricity grid, and industrial drives, is investigated. It is shown that by wider adoption of power electronics in these areas, the current European Union electricity consumption could be reduced by 25%. The technology challenges for exploiting this potential for all the four areas are identified in the paper.

Power Electronics Enabling Efficient Energy Usage: Energy Savings Potential and Technological Challenges

The electrostatic behaviour of micromachined cantilevers incorporating residual stress gradient and non-ideal anchors is studied in this work. Using finite-element simulation data, behavioural models that predict the electrostatic deflection and pull-in voltage of such structures have been established. The models account for the effects of residual stress gradient and real supports on the mechanical behaviour of the microcantilevers, and have been validated via comparison with experimental data. For the deflection models, the level of correlation achieved was within 7%, and in the case of pull-in voltage analysis, the calculated and measured values agree to within 4%. The completed models offer an efficient means of design, analysis and optimization of cantilever-based electrostatically actuated MEMS devices. They can also be utilized for material property measurement and analysis.

Nicolas Cordero

Papers

Liquid cooling of bright LEDs for automotive applications

Liquid Cooling of Bright LEDs for Automotive Applications

Power Electronics Enabling Efficient Energy Usage: Energy Savings Potential and Technological Challenges

Modelling electrostatic behaviour of microcantilevers incorporating residual stress gradient and non-ideal anchors

Spring Constant Models for Analysis and Design of MEMS Plates on Straight or Meander Tethers