Research Projects | Department of Electrical and Electronic Engineering

Project: FAST Battery Charger

DEEE Members: Prof. S.G. Abeyratne
This project is sponsored by the CodeGen International (Pvt) Ltd.

Overview

Project Summary

Electric vehicles are utilized globally as an effective eco-friendly solution to fulfill the transportation demand.

There are technical challenges to the battery charging process as it requires to use a fast-charger without accelerated battery-degradation.

Pulse charging technology is being investigated in battery charging methods due to some inherent advantages compared to other charging methods.

Several studies on pulse charging claim to have beneficial effects on charging efficiency, charging time, and capacity fade.

The goal of this research is to physically test the pulse charging method and compare it with the constant current charging method to identify favorable charging parameters.

KEY PUBLICATIONS

⮚ B.L.L. Sandaruwan, S.G. Abeyratne and R.T.T. De Silva, "Voltage-Mode-Current-Control Concept for Current-Source- Inverters in Grid Integration," PCIM Europe 2019; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management, Nuremberg, Germany, 2019, pp. 1-6.

Project: Nearshore Wave Concentration for Mechanical and Electrical Energy Generation

DEEE Members: Dr. K.D.R. Jagath Kumara.
This project was supported by the Department of Civil Engineering and the workshops of the Departments of Mechanical Engineering and the Electrical & Electronic Engineering.

Overview

Project Summary

Waves are made to propagate in an open converging channel section in order to increase the energy flux and to capture higher energy with relatively smaller devices.

Level of concentration (w1/w2) could be increased causing wave breaking and increasing the forward momentum so that hydro-turbines could be used for energy conversion.

Increase in energy flux was found to correspond to the level of concentration according to the wave flume tests in the laboratory.

Energy conversion efficiency, in some cases, was estimated to be as high as 40% from the tests carried out with horizontal-axis, axial flow turbines.

Using the mode theory for open channel wave propagation and linear wave theory it was proved mathematically that the increase in energy flux is equal to the level of concentration before breaking.

Using additional empirical results and formula it was possible to estimate the location of wave breaking inside a concentrator placed in the wave shoaling region in the nearshore.

Best location (P1, P2 or P3 etc.) for a wave concentrator in the nearshore could be found using these estimations.

KEY PUBLICATIONS

⮚ K.D.R. Jagath Kumara, (2022), “On the placement of a wave manipulator suitable for energy harnessing in the nearshore”, Taylor and Francis Cogent Engineering, Vol. 9, Issue 1, September.

⮚ K.D.R. Jagath-Kumara, D.D. Dias, R. L. Nawagamuwa, W. M. A. R. Weerasinghe, (2018), “Wave Energy Enhancement for Nearshore Electricity Generation”, ENGINEER, Journal of the Institution of Engineers, Sri Lanka, Vol. LI, No. 2, p. 43-52, April.

⮚ K.D.R. Jagath-Kumara, D.D. Dias, (2015), “Near Shore Wave Manipulation for Electricity Generation”, WASET International Journal of Energy and Power Engineering, Vol. 9, No. 7, 2015, pp. 683-692.

⮚ S.D.K. Maliyadda, W.M.C.R. Wijeratne, S.R.L.M. Zoysa, D.D. Dias, K.D.R. Jagath-Kumara (2014), “Manipulation of near-shore sea waves for electricity generation: modelling a wave concentrator,” in Proc. 5th International Conference on Sustainable Built Environment, ICSBE 2014, Kandy, Sri Lanka, vol. 3, pp. 206-216, 12-14 Dec.

Project: Top-Mounted Point Absorber Type Wave Energy Converters

DEEE Members: Dr. K.D.R. Jagath Kumara.
This project compares possible configurations for a point absorber (PA) type wave energy convertor (WECs) using semi-theoretical approaches.

Overview

Project Summary

Mounting the power take-off assembly of PA type WECs above sea level has several advantages (easy accessibility, can be shielded from salt sprays easily).

Type I: A bi-directional generator coupled to a gear wheel is driven by a chain connected to a buoy. The top end of the chain is connected to a spring to store and release potential energy. A surge converter for absorbing surge forces too is included.

Hydrodynamic parameters such as added mass and radiation (from simulations), wave dynamic pressure, buoy mass, buoyancy, spring stiffness and the generator damping is considered in the theoretical analysis.

Natural frequency of the system was found to be about 3 times higher than the significant frequencies of the sea wave spectrum.

Absorbed power were estimated for monochromatic waves, JONSWAP deep sea spectrums, TMA nearshore spectrums and concentrated TMA waves for different levels of generator damping (Bpto).

Possibility of the buoy becoming airborne was checked in each calculation and Bpto was increased to avoid such occurrences. Levels of absorbed power were found to be either slightly higher or similar to those mentioned in other publications.

It was noted that a high proportion of power is contributed from the high frequency components although the energy fluxes of them is small. This is because the absorbed power is proportional to the square of the frequency.

Type II: Therefore, two generators are coupled to a pair of counter rotating flywheels connected to the gear wheel in order to decrease the natural frequency and to convert high energy fluxes of low frequency waves.

KEY PUBLICATIONS

⮚ K.D.R. Jagath Kumara, (2022), “On the placement of a wave manipulator suitable for energy harnessing in the nearshore”, Taylor and Francis Cogent Engineering, Vol. 9, Issue 1, September.