Shahab Yousefizad - Academia.edu (original) (raw)
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Papers by Shahab Yousefizad
Researchers try to improve the multilevel inverters performance or make them more economically pr... more Researchers try to improve the multilevel inverters performance or make them more economically proposing new switching algorithms or novel structures. In this paper, a new structure is proposed for symmetric cascaded multilevel inverter which has a simpler structure and uses fewer power switches compared to conventional cascaded inverter. The reduction in the number of power electronic devices will result in the reduction of the economic cost, installation area and switching losses. The proposed structure consists of a number of separate voltage sources at the input side to generate different voltage levels and an H-bridge at the output side. Switches also connect the input voltage sources to the output in a direct form or in series. Input sources can be isolated batteries or renewable energy sources such as solar cells and or fuel cells. Using fundamental switching frequency, the proposed inverter capable of generating 7 levels of voltage at the output, is simulated by use of MATLA...
International Journal of Electronics
Researchers try to enhance the efficiency and quality of the output power of multilevel inverters... more Researchers try to enhance the efficiency and quality of the output power of multilevel inverters by use of new topologies or enhanced switching algorithms. But it should be noted that, it is not easy to change the inverter switching algorithm and doing this will increases the costs. Also these algorithms are not usually extensible to all inverter types. By considering these limitations, in this paper the THD equation of the output voltage of an asymmetric single phase cascaded multilevel inverter capable of generating 9 output voltage levels is extracted. This equation will be a function of switching angles and input voltage source values. Now, with the use of genetic algorithm which is one of the strongest optimization tools, the voltage THD is minimized and the optimized switching angles are obtained. By applying these angles in the conventional switching algorithm with fundamental frequency, the quality of the output voltage reaches its highest level. The method used in this paper is simpler than the switching algorithm changing method and can be generalized to different types of multilevel inverters. Also the use of fundamental switching frequency, will reduce switching losses. The simulation results obtained by MATLAB/SIMULINK software, confirm the performance accuracy of the proposed method.
Researchers try to improve the multilevel inverters performance or make them more economically pr... more Researchers try to improve the multilevel inverters performance or make them more economically proposing new switching algorithms or novel structures. In this paper, a new structure is proposed for symmetric cascaded multilevel inverter which has a simpler structure and uses fewer power switches compared to conventional cascaded inverter. The reduction in the number of power electronic devices will result in the reduction of the economic cost, installation area and switching losses. The proposed structure consists of a number of separate voltage sources at the input side to generate different voltage levels and an H-bridge at the output side. Switches also connect the input voltage sources to the output in a direct form or in series. Input sources can be isolated batteries or renewable energy sources such as solar cells and or fuel cells. Using fundamental switching frequency, the proposed inverter capable of generating 7 levels of voltage at the output, is simulated by use of MATLA...
International Journal of Electronics
Researchers try to enhance the efficiency and quality of the output power of multilevel inverters... more Researchers try to enhance the efficiency and quality of the output power of multilevel inverters by use of new topologies or enhanced switching algorithms. But it should be noted that, it is not easy to change the inverter switching algorithm and doing this will increases the costs. Also these algorithms are not usually extensible to all inverter types. By considering these limitations, in this paper the THD equation of the output voltage of an asymmetric single phase cascaded multilevel inverter capable of generating 9 output voltage levels is extracted. This equation will be a function of switching angles and input voltage source values. Now, with the use of genetic algorithm which is one of the strongest optimization tools, the voltage THD is minimized and the optimized switching angles are obtained. By applying these angles in the conventional switching algorithm with fundamental frequency, the quality of the output voltage reaches its highest level. The method used in this paper is simpler than the switching algorithm changing method and can be generalized to different types of multilevel inverters. Also the use of fundamental switching frequency, will reduce switching losses. The simulation results obtained by MATLAB/SIMULINK software, confirm the performance accuracy of the proposed method.