The power electronics field is undergoing large transformations through the continuous advancements of the power semiconductor industry. This led to the development of novel power converters, pulse width modulation schemes and advanced control techniques due to the wide variety of applications which have risen. Power electronic converters play a fundamental role in switch-mode power supplies (SMPS), renewable energy sources (RES) and their integration into the grid, electrical drives, electrical transportation technologies and energy storage to name a few important categories.
Direct AC/AC conversion is a desirable option in various applications such as AC motor drives and grid-connection of AC sources such as wind and wave energy conversion systems. Present electrical conversion implements a two-stage system which initially rectifies the variable voltage and variable frequency output of the electric generator into a DC voltage. The second stage is the conversion of the DC voltage to an AC voltage via a grid-tied inverter. However, these systems result in a reduced efficiency due to the required conversion processes. Therefore, direct AC/AC conversion can be employed to reduce the power conversion stages and improve the overall system efficiency.
Novel power electronic converters strive towards achieving the maximum efficiencies by design of application specific power converters and their advanced control techniques. Research topics of the department that are related to this field include (but are not limited to):
Closed loop control of electrical machines requires knowledge of the rotational speed of the rotor and the instantaneous rotor position with respect to an initial reference. Mechanical sensors are usually connected to the motor shaft to provide both functions. However, these sensors present several disadvantages including additional cost, an increase in the size of the electrical machine, reduced reliability, and susceptibility to noise (or other power quality/EMC issues).
Therefore, electrical drives without mechanical sensors connected to the motor shaft are an attractive concept due to their low cost and higher reliability. Research topics of the department that are related to this field are focused on development of sensor-less algorithms for electrical drives. These include (but are not limited to):
Microgrids are self-contained low or medium voltage (LV/MV) electrical networks that can be interfaced to conventional or smart grids. Microgrids can also function as an autonomous electrical network. Each microgrid has its own distributed generation, typically renewable energy sources (RES), energy storage systems (ESS) and loads working together as a single entity. Microgrids can allow higher penetrations of RES into the grid and therefore play an important role in current transformation of the electric grid.
DC power has also regained popularity in recent years due to the fact that distributed generation (e.g. photovoltaics,...), ESS (e.g. batteries, ...) and loads (e.g. LED lighting technologies, portable electronic equipment such as laptops and smart phones, ... ) all require DC power to operate. DC microgrids are gaining popularity as the future solution towards integration of these sources and loads since the energy efficiency can be significantly improved. Research topics of the department that are related to this field are focused on different aspects of AC, DC and hybrid microgrids. These include (but are not limited to):
Smart grids are electrical grids with detailed monitoring of energy flows and autonomous decentralized energy balancing between power supply and demand through the introduction of distributed generation. To date, several countries have started deploying smart metering as a basis to set up smart electrical grids. Most system setups are concerned on data collection to optimize the performance of the present resources.
There are various benefits associated with a smarter electrical network. The consumer shall be able to gain important knowledge on the domestic energy consumption and, regulate the energy usage hence participating in increasing energy efficiency. The supplier shall benefit from such a system in various areas: such as electricity theft, peak load shaving, maintenance planning and overall energy efficiency. However, the operation of the smart grid is not limited only to smart metering but it includes a variety of system components including distributed power generation such as renewable energy sources (RES), smart distribution networks and protection and smart appliances.
Research topics of the department that are related to this field are focused on different aspects of Smart Grids. These include (but are not limited to):
In recent years, EU policies were directed towards integration of distributed generation (DG) into the grid in an attempt to reduce the carbon emissions by the respective European countries. DG namely implies small-scale electricity generation consisting mainly of renewable energy sources (RES) such as photovoltaics systems and wind generation systems.
Renewable energy targets for the Maltese islands are were set to 10% by 2020 and government grants have been targeted towards increasing photovoltaic (PV) systems in the domestic, public, commercial and industrial areas. RES connected to the Maltese grid are all configured to supply all their energy into the grid. However, RES are intermittent in nature due to the availability of the source (eg: sun, wind, wave,...) and therefore high market penetrations of RES may cause stability issues to the electrical grid. Therefore, insight on the impact of integrating high penetrations of RES on the electrical grid is required. Research topics of the department that are related to this field include (but are not limited to):
Modern society is highly dependent on electrical energy. It is considered as a basic necessity which has transformed and is continuing to transform our everyday actions and activities. Electrical power systems are concerned with methods of generation, transmission, distribution and consumption of electrical energy. In the last decade, electrical power systems have started a worldwide slow transformation into the more intelligent electrical networks which have been termed as 'Smart Grids'. The smart grid plays an important role in reducing the greenhouse emissions, enabling high penetrations of RES, improving the reliability and improving the overall energy efficiency.
Research topics of the department that are related to this field are focused on different aspects of electrical power systems. These include (but are not limited to):
The electrification of transportation technologies is an important step towards reducing green house pollutants such as CO2 and NOx. Charging of electrical transportation from fossil fuel based generation does not give the maximum benefits with respect to reduction of green house gases. By employing electricity obtained from renewable energy sources, electric transportation technologies are 100% pollution free and environment friendly. The development of electric passenger cars has reached a level of performance which is superior to that of combustion engines. The biggest hurdle that hinders the usage of electric vehicles is the limited electrical energy which can be stored on-board since energy densities of battery technologies are still lagging significantly behind the energy density provided by fuels such as diesel or petrol. Other transportation methods also being converted into electric-powered systems. These include light electric vehicles such as electric bike and scooters, commercial and industrial use of non-road vehicles such as forklifts, cranes and tractors; electric ships and boats; electric aircraft; and rail-road transportation systems.
Our research focuses on different aspects of electric transportation technologies. These areas include (but are not limited to):
One main disadvantage of electrical energy is that it cannot be easily stored on a large scale and hence almost all electric energy used today is consumed as it is generated. This poses no problems in conventional power plants, in which fuel consumption is continuously varied with the load demand. Wind and photovoltaics, being intermittent sources of power, cannot meet the load demand at all times, 24 hours a day and 365 days a year. Therefore, energy storage is a desired feature which must be incorporated in modern power systems to improve the energy availability. The importance of energy storage is more pronounced particularly in stand-alone systems. In such cases, energy storage technologies must also be employed to provide ancillary services to the islanded grid.
Research topics of the department that are related to this field are focused on different aspects of energy storage. These include (but are not limited to):
The power quality of electrical distribution networks is affected by various electromagnetic phenomena. Nowadays, these phenomena are an important concern due to the increase in electrical and electronic equipment. These loads are the major culprits which cause power quality issues but they are also the victims of power quality problems.
International standards regulate the effect that loads or distributed generators have at their respective connection point with the grid (commonly termed as the point of common coupling or PCC). These standards ensure that grid-connected equipment can operate with the expected performance without degrading the operation of other equipment connected to the electrical grid.
Power quality issues have a significant impact on the efficiency of grid-connected equipment and therefore must be given importance. Research topics of the department of IEPC related to this field are focused on different power quality aspects, which are mainly categorized under the conducted low-frequency phenomena group. These include (but are not limited to):
Electrical building services are concerned with the design of electrical illumination, electrical installations, heating, ventilation and air conditioning (HVAC). Energy efficiency in buildings has become a major concern in recent years. In an attempt to reduce greenhouse gases the Energy Efficiency Directive set by the EU in 2012 establishes methods to use energy more efficiently from its production to its consumption. The energy efficiency target for the EU in 2020 is of 20% of the projected energy use. Under this directive, the indicative Maltese energy efficiency target in 2020 is of 22%.
The main potential for improving energy efficiency lies in industrial, commercial and residential sectors. Applications include heating, ventilation and airconditioning; home appliances; pumps; escalators; and lifts (elevators). A common denominator of these applications are electrical drives whereby industry accounts for the largest amount of total electricity consumption in various forms of mechanical handling and processing machinery.
Research topics of the department of IEPC related to this field are focused on different aspects of building service design for energy efficient buildings. These include (but are not limited to):
The Energy Efficiency Directive (2012/27/EU) set in 2012 establishes methods to use energy more efficiently from its production to its consumption, in an attempt to reduce greenhouse gases. The energy efficiency target for the EU in 2020 is of 20% of the projected energy use. Under this directive, the indicative Maltese energy efficiency target in 2020 is of 22%.
The power generation and distribution sectors are undergoing various transformations and energy efficiency is a prime cause. An example is the increase in decentralisation of the power system so as to reduce transmission losses and reduce carbon emissions. The local scenario reflects also this transformation due to the increase in penetration of RES and the link set-up with the European grid through the Malta-Sicily interconnector.
Research topics of the department of IEPC related to this field are focused on different aspects of electrical energy efficiency. These include (but are not limited to):
