To transition towards more sustainable electrical power systems, research at LAPCSA targets three critical areas of research. These areas can be categorized as (1) power systems, (2) HVDC and FACTS, (3) renewable energy and energy storage integration, and (4) electric mobility.
Power systems analysis
The modern grid is undergoing an evolution where standard methods of operation and control must be called into question due to the proliferation of renewable resources. As additional renewable resources are brought online, power converters must be used to interface them to the grid. One branch of research in the lab is the nonlinear modelling of the impact of these converters on the grid system to assess harmonics and voltage stability. Furthermore, grid resilience is also of importance where intelligent electronic devices across the grid can enable seamless operation of power systems on a speed never seen before due to the integration of high speed communication to the existing grid, thus enabling smart grids. Research in the lab is on the integration and use of phasor measurement units (PMUs) and smart grids with intelligent electronic devices. In addition, analysis and dynamic control of ac and dc micro-grids will enable operation and interconnection of smart communities to the grid.
HVDC and FACTS
Power transmission and grid support using High-Voltage DC (HVDC) systems and Flexible AC Transmission Systems (FACTS) are a necessity to modern grids. These systems enable long distance transfer of energy to interconnect generating resources with loads or interconnect neighbouring grid systems to improve energy security. When transferring power, power has been traditional transferred using ac grid system. However, transferring power across long distances and between jurisdictions introduce challenges in grid stability and security to which FACTS devices can be employed as a solution. In addition, HVDC systems can be used to interconnect two neighbouring grid systems to increase grid security. HVDC systems are also used for long distance transmission of power as DC transmission becomes more effective than AC after certain distances. With recent technology advances, DC transmission also presents an opportunity to further increase grid stability and transmission as hybrid DC and AC transmission systems have been envisioned with the aim to create ‘supergrids’, which can interconnect countries and even continents. Research in the lab focuses upon HVDC and FACTS converters with recent efforts directed in achieving objectives like power flow control in HVDC networks, large-scale integration of energy storage in dc / ac networks, and interconnection of dc networks. Such systems are subject to stringent fault handling, reliability and size constraints as a single HVDC or FACTS converter will operate, at minimum, for a decade and occupy entire the space of entire warehouses.
Renewable energy and energy storage integration
Climate change is a reality and renewable resources are key to the global reduction of greenhouse gases. However, large solar or wind farms face challenges in interconnecting these resources to the grid both from a power electronics and dispatch perspective. Research in this lab aims to integrate renewable resources with ultra-high efficiency converters and investigate means of using energy storage sources, like batteries or supercapacitors, to fully utilize these weather dependent resources.
Alternatively, dc and ac microgrids can also integrate renewable energy sources (i.e. solar, wind) and provide storage to existing grid infrastructure in a distributed manner as opposed to classical large-scale generation plants like wind or solar farms. DC microgrids offer better power conversion semiconductor utilization and efficiency while integrating well with existing energy storage technology (eg. batteries) and generation sources (eg. solar). Research is focused towards modelling and low-level / high-level control of DC microgrids. State-space modelling, eigenvalue analysis, power electronics design and control schemes are researched to investigate DC microgrid feasibility and power scalability. High-level control and energy management techniques are investigated to provide further support to existing grid infrastructures and increasing system robustness/reliability. DC microgrid physical set-up being designed in Galbraith Building to power indoor lighting and other loads by utilizing PV technology on roof and available energy storage mediums. Research will include gathering experimental data and investigating/overcoming practical barriers (eg. EMI, sensor errors).
Electric mobility
Electric mobility represents a evolution in our transportation sector. Previous attempts at the electrification of vehicles have failed primarily due to range anxiety. Specifically, vehicles were not able to travel long distances and vehicles could not be charge conveniently and quickly. To combat range anxiety, research in the lab focuses upon drivetrain improvements and facilitation of vehicle charging.
To improve vehicle range, research at the lab has been focusing on improved drivetrains for electric vehicles through alternative drive system power electronics and advanced control techniques for hybrid energy storage integration and management. The focus of hybrid energy storage is to integrate different energy storage media (i.e. batteries, supercapacitors, or fuel cells) together to best utilize their inherent characteristics. For example, batteries are have a better energy rating than power, thus they can be complimented with supercapacitors that have a better power rating than energy. Supercapacitors can source all transient power requirements for the vehicle, while the battery provides the majority of the steady state power.
Our main focus in the area of electric vehicle (EV) conductive charging is to develop state-of-the-art power electronics that promote rapid expansion of a stable EV charging infrastructure for the advancement of electric vehicles. Â Development of advanced power electronics for electric vehicle charging with key focus on (1) modeling and analysis of new converter topologies, (2) smart charging methods, and (3) power quality and grid impact assessment.
To compliment conductive charging infrastructure, research at the lab also focuses upon wireless charging as it represents a convenient method of charging for everyday users. However, these systems are not as efficient as corded solutions. The highest source of loss comes from the coil topology and the alignment of the transmitter and receiver coils. For the highest efficiency to be reached the driver needs to park the EV exactly on top of the transmitter, with perfect transversal and longitudinal alignment. Such perfect parking is rarely the case. Thus, the coupling of transmitter and receiver coils drops rapidly for few tenths of centimeters of misalignment, reducing the efficiency drastically. Our research main focuses are in the study and development of coil topologies that are capable of enhancing the magnetic coupling through magnetic field modeling; and the development of power converters for inductive power transfer systems.