Papers by NAGESH KUDUPUDI
International Journal of Engineering and Technology, 2017
A novel method for a 3-phase nine-level voltage source inverter using sixteen switch is introduce... more A novel method for a 3-phase nine-level voltage source inverter using sixteen switch is introduced. The given technique employs conventional 3-phase bridges of two-level as a diode clamped model. A dc link voltage is supplied in such a way that the cascaded H-bridge produces the nine voltage levels. The switching patterns are stated as the levels increases then the pattern is difficult to produce three-phase outputs with fundamental modulation techniques. Here a solution for n-level inverter to produce required voltage-level with less number of power electronic components by setting up in the look-up tables. This study outlines the comparisons between nine-level voltage source inverters in different configurations and proposed novel sixteen switch three-phase inverter designed with less number of power electronic components and simulated in MATLAB/SIMULINK.
—A novel method for a 3-phase nine-level voltage source inverter using sixteen switch is introduc... more —A novel method for a 3-phase nine-level voltage source inverter using sixteen switch is introduced. The given technique employs conventional 3-phase bridges of two-level as a diode clamped model. A dc link voltage is supplied in such a way that the cascaded H-bridge produces the nine voltage levels. The switching patterns are stated as the levels increases then the pattern is difficult to produce three-phase outputs with fundamental modulation techniques. Here a solution for n-level inverter to produce required voltage-level with less number of power electronic components by setting up in the look-up tables. This study outlines the comparisons between nine-level voltage source inverters in different configurations and proposed novel sixteen switch three-phase inverter designed with less number of power electronic components and simulated in MATLAB/SIMULINK. The conventional voltage source inverter enables the synthesis of sinusoidal output voltage from several steps of voltages. The word multilevel has started with the three-level converter followed by numerous multilevel converter topologies. A wide range of topologies and control strategies are presented in literature [1]-[3]. A stack of multilevel inverter modules is designed for achieving low dv/dt characteristics, low switching losses low harmonics in the output voltage and current and better electromagnetic interference. Due to several advantages, multilevel inverters have been applied in various application fields [4]-[8]. The cascaded multilevel inverter is developed by a number of single-phase H-bridge inverters and is categorized into symmetric and asymmetric based on the magnitude of the dc voltage sources. In the symmetric multilevel inverter, the magnitudes of the dc voltages are equal while, the asymmetric multilevel inverter, the values of the dc voltages are unequal. Recently, asymmetrical multilevel inverter and hybrid multistage topologies are becoming on of the most interested research area. This topology reduces the cost and size of the inverter and improves the reliability since minimum number of power electronic components, capacitors, and dc supplies used. The hybrid multistage converters consist of different multilevel configurations with unequal dc voltage supplies. With such converters, different modulation strategies and power electronic components technologies are needed [9]– [15]. However, the purpose of improving the performance of the conventional single and three-phase inverters, different topologies employed with different types of bidirectional switches has presented. By comparing the unidirectional and bidirectional switches, bidirectional switch is capable to conduct the current and withstanding the voltage in two-directions. For achieving the higher voltage levels, bidirectional switches with an appropriate modulation technique can improve the performance of voltage source inverter in terms of reducing the semiconductor components and minimizing the withstanding voltages. Based on the technical background, this paper suggests a novel topology for a three-phase nine-level voltage source inverter with sixteen switches. Also extended structure for N-level is presented and compared by different trending topologies. II. PROPOSED TOPOLOGY A. Modelling The proposed nine level voltage source inverter consists three-bidirectional switches (S1-S6), two diodes (Da1-Da2), are added to the conventional three-phase two-level bridge (Q1-Q6) as shown in Fig.1. The function of these bidirectional switches is to block the higher voltage and ease current flow to and from the midpoint (o). There by VSI is fed with a fixed voltage of 4Vdc and two cascaded bridges are fed with to unequal voltages Vdc and 2Vdc are connected to (+,-, o) terminals. Hence the presented VSI is functioned to generate nine equal and different voltage levels, the power circuit of the cascaded H-bridge makes use of two series cells having unequal voltage supplies. In each cell two switches are turned On and OFF under inverted conditions to output two voltage levels.
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Papers by NAGESH KUDUPUDI