Standardization saves time in the design and this fact leads to better products. This concept can be extended to power electronics, but it is very difficult to standardize all applications in power electronics because the ranges of variation of specifications (i.e. switching frequency, voltage, power, etc.) are wide. Fortunately, modularization helps to overcome this problem, since the grouping power converters allow the capacity to handle higher power levels, to handle high input voltages and to generate high output voltages. In other words, it is possible to use groups of standard power converters ("cell converters") to built a power converter with different specifications (higher power and higher or equal input and output voltages). The research in this case is focused on determining the topologies, working modes and control strategies that determines the best scenario "cell converter" and the strategy of joint operation of all cells.

LEDs emitting white light are considered the foremost alternative to replace inefficient light sources (e.g. incandescent, halogen, fluorescent, compact fluorescent sources, etc.). Nowadays, due to reductions in manufacturing cost, LEDs are increasingly becoming our main source of artificial light in many applications (e.g. street lighting, automotive, residential lighting, etc.). The reason why LEDs have been so successful in the lighting market lies in their excellent characteristics in comparison to conventional lighting solutions: long lifetime, low maintenance requirements, environment friendliness, luminous efficiency, controllability in both light and color, lack of warm-up period, reliability and high power density.

Given that LEDs are diodes, it is necessary to control their dc forward current. The devices fulfilling this task are known as LED drivers. It is essential that these devices do not limit the benefits and performance of LEDs. Therefore, LED drivers must be as efficient, compact and durable as LEDs, comply with very strict regulations and adequately control the output current. These requirements have made the driving of LED lamps a significant field of research in power electronics, where the main topics of interest are: LED modelling, ac-dc LED drivers, dc-dc LED drivers, efficient dimming and efficient current equalizing in multi-array LED lamps.

This research line tries to assess the advantages and limitations of residential LVDC distribution. It is well known that great part of the loads connected to home mains are DC loads (LED lighting, consumer electronics devices, battery chargers, etc.) and another important part is not DC loads needs a Ac/DC conversion before acquiring its final format (AC drives for motors, for example). For this reason, residential LVDC distribution could have important advantages in saving power electronic converters to adapt the final format of electrical energy in homes (which means energy savings), but on the contrary, it requires an standardization in regards possible solutions. This research line face this challenge designing and testing different “bus providers” for residential LVDC distribution as original contribution in the DC distribution in homes

Efficient power converters able to change their output voltage in the microsecond scale and beyond play a major role in very fast response applications. SEA-UNIOVI group has involved with very relevant and original contributions in the last 10 years in this topic for specific applications: Envelope Tracking, ET, and Visible Light Communications, VLC. The difference between both applications is the load connected to the output of the converters. In the first case, ET, very fast response converters supplies a Radio Frequency Power Amplifier (APRF) in order to improve its efficiency. In second case, VLC, the very fast response converters supplies LED loads, which have double function: illumination and communication.

Current trends in very fast response converters are twofold: first, operation at high switching frequency (MHz range) naturally allows faster response and higher bandwidth. Second, novel circuit topologies, architectures and control techniques can enable faster dynamics at lower switching frequencies, making it easier to achieve high efficiencies. In both cases, many challenges arise around the converter design: frequency-dependent loss mechanisms in active and passive device,s influence of parasitic elements, design of low-loss reactive components capable of operating at high frequencies, optimal utilization of wide band-gap power devices, implementation of adequate control circuitry (analog, digital or mixed-signal), design of high-bandwidth control loops, etc.

Si based power electronic device technology is mature. However, there are research topic related with its modelling, and the application of these models in order to assess power losses and thermal management in power electronic converters. We will continue analysing the application of Si power electronic devices, developed by different companies, in massively used power converters.

Gallium Nitride (GaN) electronic devices have been used for many years in RF applications. However, its use in power electronics is relatively recent. GaN. Nowadays, you can find commercial High-Electron-Mobility Transistor (HEMT) made with GaN for very high frequencu applications. Some challenges of this topic, which are faced by SEA-UNIOVI, are the following ones: the driving of these devices (being, in some cases, "normally off" switches), the definition of specific applications in which their advantages overcomes their higher cost and the search for specific topologies of power converters.

Silicon carbide (SiC) electronic devices have breakdown electric fields clearly higher Si electronic devices (between 7 and 10 times greater), which makes them very suitable for high voltages applications. The thermal conductivity of SiC is three times higher than silicon (Si). Both characteristics, makes SiC power devices suitable for high power applications, where thermal management and switching at high voltage levels and high frequencies is now possible for specific applications: more electric aircraft, railway, electric vehicle, solid state transformers, integration of renewable energies, smart-grids, etc.

Electric mobility will be the next disruption. During the last year, power electronic systems on board in the different types of transport (air, sea, and land) have been evolving and increasing day by day. The objectives of this line are the general ones of power electronics in terms of improving performance, costs, dynamic responses, reliability, size, weight and cost. The last three ones are the main concerns in the design of power converters that define the power systems of these applications: more electric aircraft, railway, electric vehicle, more electric ship, etc.

Power electronics transformers (PETs), also called Solid-State Transformers, are envisioned as a semiconductor based alternative to conventional line-frequency Transformers (LFTs). PETs are expected to beat the LFTs in terms of power density and much superior functionalities but would be inferior in terms of cost, efficiency (full load), and reliability. Based on the modular approach, the use of multilevel converters to develop some stages of the PET is very common. This research line is an extension of previous: Modular power converters.

Modeling of dc-dc converters

Dc-dc converters with synchronous rectification

Modeling of single-phase Power Factor Correctors (PFCs)

Integrated (single-stage) single-phase PFCs.

High-density dc-dc converters

Improvements in Uninterruptible Power Supplies (UPSs)

Dc-dc converters with synchronous for telecom applications.

Magnetic design