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M. G. HOSSEINI AGHDAM,S. H. FATHI,G. B. GHAREHPETIAN 전력전자학회 2007 ICPE(ISPE)논문집 Vol.- No.-
One of the major problems in electric power quality is the harmonic contents. There are several methods of indicating the quantity of harmonic contents. The most widely used measure is the total harmonic distortion (THD). This paper compares the two harmonic optimization techniques, optimal minimization of the total harmonic distortion (OMTHD) technique and optimized harmonic stepped-waveform (OHSW) technique used in multi-level voltage-source inverters. Both techniques are very effective and efficient for improving the quality of the inverter output voltage. First, we describe briefly the cascaded H-bridge multi-level inverter structure. Then, we present the switching algorithm for the inverter based on OHSW and OMTHD techniques. Finally, the results obtained by simulation for the two techniques are analyzed and compared. Simulation results verify the effectiveness of the both techniques in multi-level voltage-source inverter with non-equal DC sources, clarifying the advantages of each technique.
A Modular DC-DC Converter with Zero Voltage Switching Capability
Seyed Hossein Hosseini,Farzad Sedaghati,Mehran Sabahi,G. B. Gharehpetian 제어로봇시스템학회 2014 제어로봇시스템학회 국제학술대회 논문집 Vol.2014 No.10
A Modular DC-DC converter with a high-frequency link and bidirectional power flow capability is presented in this paper. Zero voltage switching (ZVS) operation without using any auxiliary circuit, is one of the most important specifications of the proposed modular DC-DC converter. Also, compatibility for high power applications and less number of switching devices are the other merits of the proposed converter. ZVS analysis of the modular converters is necessary because of their high power applications and high number of power switches. The ZVS condition of the proposed modular DC-DC converter is studied and its criteria are derived in detail. The operation principle of the proposed converter, and its ZVS operation are verified using both simulation and experimental measurement.
Hamid Radmanesh,S.H.Fathi,G.B. Gharehpetian 대한전기학회 2016 Journal of Electrical Engineering & Technology Vol.11 No.5
Recently, various types of Solid State Fault Current Limiters (SSFCLs) have been proposed. These SSFCLs can improve the voltage quality, decrease the transmission losses, and also can enhance the distribution network stability but there are some practical problems with these FCLs. This paper proposes a modified FCL with focusing on the components optimization, efficiency improvement and reducing the cost. The suggested FCL uses a series AC reactor with controllable power electronic switches named Thyristor-Controlled AC Reactor (TCAR) which is connected in series with the feeder to limit the fault current and avoid fault current problems, which impairs overall distribution network reliability. The influence of TCAR on the fault current is analyzed using analytical, simulation and laboratory tests. The performance of the proposed TCAR in the simple distribution network is examined. The simulation and experimental results are in a good agreement with together and show the proper operation of the proposed TCAR during the normal and fault operation modes.