iosr-JEEE   Volume-8 ~ Issue-5

Abstract: An isolated buck–boost dc/dc converter for wide input-voltage range is proposed in this paper, and the full- bridge (FB) boost converter, being one of the typical topologies, is analyzed. Due to the existence of the resonant inductor (including the leakage inductor), the FB-boost converter can only adopt the two-edge-modulation (TEM) scheme with the FB cell being leading-edge modulated and the boost cell being trailing-edge modulated to minimize the inductor current ripple over the input- voltage range, and a phase-shift-control-scheme-based TEM with the use of the market available controller IC such as UC3895 is pro- posed, which realizes phase-shifted control for the FB cell to achieve zero-voltage switching. In order to improve the reliability and efficiency of the FB-boost converter, a three-mode dual-frequency control scheme is proposed, in which the FB-boost converter operates in boost, FB-boost and FB modes in low, medium and high input voltage regions, respectively, and for which the expression of the inductor current ripple is derived in this paper. As the input voltage in the FB-boost mode is close to the output voltage, the inductor current ripple in this mode is much smaller than that in the other modes, and the switching frequency of the boost cell in this mode can be lowered to one-(2N+1)th of the preset switching frequency to reduce the switching loss, and hence, to improve the efficiency. A 250–500 V input, 360 V output, and 6 kW rated power prototype is fabricated to verify the effectiveness of the design and control method. The average efficiency over the input-voltage range is 96.5%, and the highest efficiency attained is 97.2%.

[1] Xinbo Ruan, Chuan Yao, Xuehua Wang and Chi K. Tse YAO et al.: ―isolated buck–boost dc/dc converters suitable for wide input-voltage range,‖ , ieee transactions on power electronics, vol. 26, no. 9, september 2011 . [2] P. G. Barbosa, H. A. C. Braga, M. C. B. Rodrigues, and E. C. Teixeira, ―Boost current multilevel inverter and its application on single-phase grid connected photovoltaic systems,‖ IEEE Trans. Power Electron., vol. 21, no. 4, pp. 1116–1124, Jul. 2006. [3] T. Shimizu, O. Hashimoto, and G. Kimura, ―A novel high-performance utility-interactive photovoltaic inverter system,‖ IEEE Trans. Power Electron., vol. 18, no. 2, pp. 704–711, Mar. 2003. [4] M. J. V. Vazquez, J. M A. Marquez, and F. S. Manzano, ―A methodology for optimizing stand-alone PV-System sizing using parallel connected dc/dc converter,‖ IEEE Trans. Ind. Electron., vol. 55, no. 7, pp. 2664– 2673, Jul. 2008. [5] T. Kerekes, R, Teodorescu, M. Liserre, C. Klumpner, and M. Sumner, ―Evaluation of three-phase transformerless photovoltaic inverter topologies,‖ IEEE Trans. Power Electron., vol. 24, no. 9, pp. 2202–2211, Sep. 2009.

Abstract: In the matrix converter (MC) system to improve the input current quality with low harmonic components, as well as to reduce the input voltage distortion supplied to the MC by using input filters. The major consequence of the paper is about the inter harmonics appearing in the induction motor drive.. In this paper, we propose a new direct space vector modulation (DSVM) method to achieve the required displacement angle between the input voltage and input current of the MC. The paper illustrates the various inter harmonics elimination methods of SVM inverter fed drive and the associated drawbacks. The drawbacks are eliminated by using New DSVM method instead of SVM method in matrix converter fed induction motor drive. A new switching strategy is introduced based on the maximum compensated angle. Then, power factor compensation algorithms using the new DSVM method to achieve the maximum IPF. In which Compensation algorithm is subsequently proposed using a proportional–integral controller to overcome drawbacks presented in compensation algorithm of SVM method. Simulation and experimental results are shown to validate the effectiveness of the proposed compensation algorithms.

Keywords: Direct space vector modulation (DSVM) method, induction motor drive, inter-harmonics, input filter, matrix converter (MC).

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Abstract: Switch Mode rectifiers for power-factor correction have gained considerable attention, due to the increasing demand for improved power quality. A new three-phase single-stage rectifier with Brushless DC motor is proposed in this paper. Each converter operates in the continuous conduction mode (CCM), which allows a high power factor and a small EMI filter. The outstanding features of the proposed rectifier are that it can produce input currents that do not have dead band regions and an output current that can be continuous when the converter is operating from maximum load to at least half of the load. Here we proposed full bridge converter with machine load condition system is validated through MATLAB/SIMULINK Platform.

Keywords: AC–DC power conversion, single-stage power factor correction (SSPFC), three-level converters, DC motor, Brushless DC motor.

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