WP18 Smart Energy Management

Led by: Dr Petar Igic, Swansea University


a. Low cost – High Performance Smart Power Conversion: Technology:

  • Gallium nitride (GaN) material and its ternary compounds possess unique material properties including polarization. GaN-based HEMTs with a low on-resistance and fast high voltage switching characteristics are leading candidates in semiconductor industry to replace silicon technology for high power and high frequency applications needed for effective and smart energy management. The GaN-based devices are the focus of a great interest in academia and industry such as electrical generation, transmission, distribution systems, and wireless communications (satellite communications, TV broadcasting, and broadband wireless internet). Although an outstanding progress was made during the last 20 years, GaN-based devices are still far from maturity mostly due to reliability reasons. The potential of GaN HEMTs to replace silicon is significantly limited by parasitic charge accumulation at the device resulting from shallow and deep defects centres. This effect introduces current collapse, the knee walkout, and increase in on-resistance of the device reducing the expected output power density under the electrical stress.

b. Low Cost – High Performance Smart Power Conversion: Converter Topology and Control Techniques:

  • Energy conversion is a major challenge in moving towards a sustainable low-carbon economy. It is an essential element of novel energy power generation system and future transportation systems. The core of an energy conversion system is the power electronics converter which in one hand ensures the maximum power capture from any energy source and on another hand controls the power quality delivered to grid. Therefore the converter parameters such as efficiency, reliability and costs are directly affecting the performance of an energy system. The various power electronics converter topologies ranging from sing-phase to three-phase, single-stage to multi-stage converters, and two levels to multi-level converters, and their control techniques needs further study to optimize above listed key parameters.

c. Low cost – High Performance Smart Power Conversion: Power System:

  1. Challenges which transmission and distribution (T&D) systems may encounter in the near future include:
  • Providing growth in electricity demand and enhancing the robustness with minimum increase in transmission lines.
  • Coping with increased penetration of renewable energy such as wind and photovoltaic systems.
  • Improving the local reliability to ensure the power quality demanded by customers.
  1. Decentralisation of generation and storage systems, or distributed generation (DG), has emerged as a promising solution for the challenges mentioned above. DG leads to the fact that in the future, generation and storage of energy in a power network will happen at two levels:
  • Centralised, using large-units, and
  • Localised, using small-units.

Consequently, in the near future, a power grid will no longer be a mono-directional energy follow system but a bi-directional one, requiring a much more complex Energy Management System (EMS). This task focuses on investigating, developing and implementing a Smart Energy Management System for future power networks.


Low cost – High Performance Smart Power Conversion: Technology:
a) The aim is: (i) to develop a simulation methodology to explain dispersive behaviour of GaN HEMTs and attribute it to different type of traps in the device using gate-lag and drain-lag techniques applied simultaneously, and (ii) to study the source-contact-resistance saturation that arises from the creation of traps on the source side of the GaN HEMTs resulting in smooth transconductance characteristics.
b) This work area will pursue research in order to:
 Mitigate the impact of different defect types of GaN HEMTs under operation.
 Minimize the generation of defects on transconductance in GaN HEMTs.
 Advance the study of defects further to alleviate their impact on the device operations.
 Improve the GaN reliability using optimization techniques.
 Evaluate wide range of off-the-shelf available GaN Power devices for use in the power conversion.
 Assess the potential of GaN HEMT based devices for a replacement of silicon technology.
c) Low Cost – High Performance Smart Power Conversion: Converter Topology and Control Techniques:
 The increase demand in power conversion widely used in renewable power systems and transportation, negative impact of non-linear loads on power quality and the continual increase on running cost have led to an urgent need to develop smart power conversion with a significant reduction in cost while improving efficiency, reliability and overall performance. To achieve these objectives new topologies are to be developed using smart compact power conversion technology alongside digital on line and real time modern control strategies. Various power converter topologies and real-time control strategies will be designed and tested based on real-time simulation using dSPACE real time simulator. Optimal PWM control strategies will be explored to minimize the converter power losses and to improve the power quality. To improve the efficiency from renewable energy various MPPT algorithms for energy systems will be investigated and assessed. The combined multi stage power conversion system that uses current and, more importantly, the newly developed power devices such as IGCT, SiC MOSFETs, and GaN HEMTs will be investigated and the impact on converter circuit complexity, size and costs, and efficiency will be explored and assessed. The advanced converter topologies and real time control strategies and their potential for industrial applications will be explored.
 This work area will pursue research in order to:
o Develop advanced PWM control strategies for power electronics converter with the aims of improvement of converter efficiency and power quality.
o Propose highly efficient and stable MPPT control strategies for effective energy capture.
o Propose and implement advanced control strategies for power converter real-time control and eliminate the effect of time delay on control loop.
o Propose and implement advanced converter topologies with the objective of reduction in cost, improvements in efficiency and reliability.
o Design and develop power converters using smart compact power conversion technology alongside digital on line and real time modern control strategies.
o Design, construct and test power converters using the newly available power devices, including SiC MOSFETS and GaN HEMT devices.
o Perform comparative study Conventional Si power converter Vs. SiC power converter Vs. GaN power converter.
d) Low cost – High Performance Smart Power Conversion: Power System:
 This sub-WP will propose a smart and comprehensive EMS capable of maintaining the security of supply through an intelligent paradigm that coordinates the control between all the centralised, as well as the localised generation, storage and demand units. Since the energy storage (ES) mechanisms are at the heart of the future power grids, a smart EMS must include the integration and control of different types of ES into the grid. This sub-WP proposes control methodologies for localised (short- and medium-terms ES) and centralised (Medium- and long-terms ES) for both islanded and grid connected applications.
 Some important aspects of such an intelligent EMS are:
o Maintaining security of supply
o Improving power quality
o Reactive power/power factor control
o Frequency control/support
o Voltage control/support
o Minimising losses through maximisation of the usage of localised generation and storage units
o Fault detection and fault ride-through mechanisms
 This work area will pursue research in order to:
o Undertake extensive study on different types of ES mechanisms and their application in power systems.
o Develop control paradigms for ES mechanisms at different levels of a power network - developing the control methods for both islanded and grid-tide applications.
o Validate the proposed control methods by using OPAL-RT “fast control prototyping”. This includes HIL capability which facilitates the validation of control methods with real hardware in the circuit.
o Propose comprehensive paradigm to coordinate the control of ES and generation units at different levels of a power system. The proposed method will be validated using OPAL-RT’s eMEGAsim power system simulator.