Agileswari K. Ramasamy
Universiti Tenaga Nasional

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Modelling of a Two-Stage Bidirectional AC-DC Converter using Wavelet Modulation H.K. Chiu; Agileswari K. Ramasamy; Nadia M.L. Tan; Matthew Y.W. Teow
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 9, No 3: September 2018
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1272.091 KB) | DOI: 10.11591/ijpeds.v9.i3.pp1006-1015

Abstract

In this paper, a Wavelet modulated isolated two-stage three-phase bidirectional AC-DC converter is proposed for electric vehicle (EV) charging systems. Half-bridge resonant CLLC converter is proposed due to its high efficiency, wide gain range, galvanic isolation and bidirectional power flow. Wavelet modulation technique is used for three-phase six leg AC-DC converter due to its benefits of high DC component and lower harmonic contents. The proposed two-stage converter is developed and simulated in MATLAB Simulink environment. The contribution of this paper is on the implementation and performance analysis of Wavelet modulation in bidirectional AC-DC converters. The results show that Wavelet modulation is suitable to be implemented for the proposed bidirectional converter. The performance of the proposed converter delivers very low output voltage ripple and total harmonic distortion output current of less than 10% which is within the expected results.
Grid reactive voltage regulation and cost optimization for electric vehicle penetration in power network Farrukh Nagi; Aidil Azwin; Navaamsini Boopalan; Agileswari K. Ramasamy; Marayati Marsadek; Syed Khaleel Ahmed
Indonesian Journal of Electrical Engineering and Computer Science Vol 25, No 2: February 2022
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v25.i2.pp741-754

Abstract

Expecting large electric vehicle (EV) usage in the future due to environmental issues, state subsidies, and incentives, the impact of EV charging on the power grid is required to be closely analyzed and studied for power quality, stability, and planning of infrastructure. When a large number of energy storage batteries are connected to the grid as a capacitive load the power factor of the power grid is inevitably reduced, causing power losses and voltage instability. In this work large-scale 18K EV charging model is implemented on IEEE 33 network. Optimization methods are described to search for the location of nodes that are affected most due to EV charging in terms of power losses and voltage instability of the network. Followed by optimized reactive power injection magnitude and time duration of reactive power at the identified nodes. It is shown that power losses are reduced and voltage stability is improved in the grid, which also complements the reduction in EV charging cost. The result will be useful for EV charging stations infrastructure planning, grid stabilization, and reducing EV charging costs.
Small Signal Stability Analysis of Grid Connected Photovoltaic Shalom Lim Zhu Aun; Marayati Bte Marsadek; Agileswari K. Ramasamy
Indonesian Journal of Electrical Engineering and Computer Science Vol 6, No 3: June 2017
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v6.i3.pp553-562

Abstract

This paper primarily focuses on the small signal stability analysis of a power system integrated with solar photovoltaics (PV). The test system used in this study is the IEEE 39-bus. The small signal stability of the test system are investigated in terms of eigenvalue analysis, damped frequency, damping ratio and participation factor. In this study, various conditions are analyzed which include the increase in solar PV penetration into the system and load variation. The results obtained indicate that there is no significant impact of solar PV penetration on the small signal stability of large scaled power system.