Raja Nor Firdaus Kashfi Raja Othman
Universiti Teknikal Malaysia Melaka (UTeM)

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Analysis of direct power control AC-DC converter under unbalance voltage supply for steady-state and dynamic response Nor Azizah Mohd Yusoff; Azziddin M. Razali; Kasrul Abdul Karim; Raja Nor Firdaus Kashfi Raja Othman; Auzani Jidin; Nor Aishah Md Zuki; Nurfaezah Abdullah
International Journal of Electrical and Computer Engineering (IJECE) Vol 10, No 4: August 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (965.145 KB) | DOI: 10.11591/ijece.v10i4.pp3333-3342

Abstract

This paper presents an analysis of Direct Power Control (DPC) technique for the Three-Phase Pulse Width Modulation (PWM) AC-DC converter under unbalanced supply condition. Unbalance condition will cause the presence of unbalanced current and voltages thus produce the negative components on the grid voltage as well as severe performance degradation of a grid connected Voltage Source Inverter (VSI). The input structures for conventional DPC has been modified with a three simpler sequence networks instead of coupled by a detailed Three-Phase system method. The imbalance voltage can be resolved by separating from the individual elements of voltage and current into symmetrical components called Sequence Network. Consequently, the input power relatively improved during unbalanced condition almost 70% through the measurement of Total Harmonic Distortion (THD) from the conventional Direct Power Control (DPC) in individual elements which is higher compared to separate components. Hence, several analyses are performed in order to analyze the steady state and dynamic performance of the converter, particularly during the load and DC voltage output reference variations.
Modelling methods and structure topology of the switched reluctance synchronous motor type machine: a review Norrimah Abdullah; Fairul Azhar Abdul Shukor; Raja Nor Firdaus Kashfi Raja Othman; Suhairi Rizuan Che Ahmad; Nur Ashikin Mohd Nasir
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 14, No 1: March 2023
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijpeds.v14.i1.pp111-122

Abstract

The switched reluctance synchronous motors (SRSM) have been utilised as replacements for induction motors (IM) and permanent magnet synchronous motors (PMSM). The SRSM is a feasible solution for electric motors because of its robust and straightforward structure, resulting in low maintenance, manufacturing, and operating costs. However, the SRSM has several flaws, including low mean torque, low torque density and excessive torque ripples. The SRSM performance can be improved by considering the structure topology and driving system. This paper reviewed the performance characteristic of SRSM based on the structural topology. Several literature studies on the segmented structure topologies of SRSM were compared with the conventional structures. The performance of the SRSM can be estimated by using either numerical or analytical methods. The FEA and BEM are numerical techniques extensively used to optimise electrical motor performance. Although the numerical method can accurately estimate motor performance, the significant drawback is quite complicated, time-consuming, and difficult to implement the control algorithm with FEA software. However, the analytical method, especially the MEC method, is faster in evaluating motor performance and significantly reduces computational complexity, either with or without solving high-dimensional system matrices.