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Volume 4, Issue 1, 2025

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In recent decades, the strategic placement of capacitors for compensating inductive reactive power has been extensively investigated by network operators and researchers globally, owing to its profound impact on minimizing power losses, improving voltage regulation, and enhancing overall voltage stability. The installation of shunt capacitors has been demonstrated to significantly improve the efficiency and performance of power systems by regulating voltage levels at load points, as well as at distribution and transmission system buses. This approach not only reduces inductive reactive power but also corrects the system’s power factor, thereby optimizing energy utilization. In this study, the optimal sizing and placement of capacitor banks within a specific section of the Duhok city distribution network were systematically analyzed. The Electrical Transient Analyzer Program (ETAP) software was employed to simulate and evaluate power losses and voltage drops both before and after capacitor installation. The findings reveal a marked improvement in the voltage profile across the network, accompanied by a substantial reduction in power losses. These results underscore the critical role of capacitor banks in enhancing the operational efficiency of distribution networks, providing a robust framework for future implementations in similar systems. The methodology and outcomes presented herein offer valuable insights for network operators seeking to optimize power system performance through reactive power compensation.

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Efficient bidirectional energy exchange between an alternating current (AC) grid and a direct current (DC) source has been enabled through advanced power converter topologies. In this study, a single-stage AC-DC dual active bridge (DAB) converter employing phase-shift modulation (PSM) was investigated, with a particular focus on performance within the overmodulation regime. Bidirectional switching modules were implemented on the AC side to facilitate seamless energy transfer. Two conventional modulation strategies—sinusoidal and triangular—and a novel back-calculated modulation method were examined for their performance in both linear and overmodulation operating regions. The proposed back-calculation method incorporates an off-line generated reference current waveform designed to approximate linear control characteristics while substantially minimizing current harmonic distortion under overmodulated conditions. This approach extends the linear relationship between the reference current and power transfer capability beyond the conventional modulation limits, thereby enhancing converter performance in high-demand scenarios. Simulation-based analysis demonstrated that, in the linear region, the proposed method reduced average current total harmonic distortion (THD) by at least 45% when compared to conventional sinusoidal and triangular modulation techniques. Moreover, within the overmodulation regime, the linear correlation between the reference current and power transfer was extended by approximately 16.5%. The current harmonic distortion remained below 5% and 8% at modulation ratios of 108% and 112%, respectively, underscoring the robustness of the proposed strategy. These results suggest that the proposed PSM method is highly effective in achieving improved power exchange with reduced harmonic content in both linear and overmodulated operation, thereby offering a viable solution for high-performance AC-DC power conversion in smart grids and renewable energy systems.

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Permanent Magnet Synchronous Motors (PMSMs) have garnered sustained attention over the past four decades due to their high efficiency, superior torque density, and dependable operational characteristics, making them highly suitable for a wide range of industrial applications. Accurate dynamic modelling of PMSMs is essential for performance evaluation and the development of advanced drive control strategies. Although previous studies have addressed customized modelling approaches for various PMSM types, a streamlined method for deriving model parameters from standard manufacturer specifications remains insufficiently explored. As a result, simulation studies are often disconnected from commercially available motor data, thereby limiting their practical relevance. In this study, the dynamic model of a PMSM is reformulated within the synchronous rotating reference frame (d-q axis) and implemented using mathematical function blocks in the MATLAB/Simulink environment. A systematic procedure is developed to extract key motor parameters from typical manufacturer data sheets. This approach bridges the gap between theoretical modeling and real-world motor implementation. The proposed modelling framework is validated using a standard 1 hp, 2.2 Nm, 1500 rpm PMSM, and its performance is benchmarked against the built-in Simulink PMSM blockset. Simulations are conducted to evaluate the mechanical output, rotor speed, and electromagnetic torque responses under step variations in load torque. The results exhibited strong agreement between the custom mathematical model and the blockset counterpart, confirming the accuracy and practical applicability of the parameter extraction methodology.
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