Modulation Index Variation Effect on Harmonic Behavior of Fifteen Multilevel Inverter Neutral-Point-Clamped Topology

Abstract

The Market for photovoltaic cells (PV) has grown fast due to a higher demand on PV applications. However, there are still the transport and connection problems of the PV systems to the grid because of the difference in the current form. To assure the adequate connection between the PV sources and the network, the conversion of direct current (DC) to an alternative current (AC) is required and provided by an electronic device known as the inverter. In this last years, the conventional inverter structure reached its limits in power level and conversion performance. The multilevel inverter (MLI) structure was introduced and widely used in high power and high voltage applications to solve the conventional inverter limitation problem. In this paper, the Neutral-Point-Clamped (NPC) topology of the MLI was simulated to evaluate the effect of modulation index variation of the control technique on the harmonic behavior of the fifteen-level NPC. The simulation results were useful for the optimization of the MLI control technique toward the decrease of the harmonic (THD) effect on the NPC MLI. Keyword:Multilevel INTRODUCTIONPhotovoltaic (PV) systems world market know a fast growth during the last year due to the necessity of developing the renewable energy to replace the fossil fuels [1]. However, this rapid growth required in parallel the improvement of the PV chain efficiency such as the PV generator energy yielding, the electrical power transport performance and the adequate connection to the grid [2]. One of the important parts of the conversion chain devices is the inverter which allows the conversion of DC signal to AC signal in purpose to permit the distribution and connection of the output electrical energy of the PV generator to the network [3]. In addition to PV conversion chain, inverters are used in power system applications and uninterrupted power supplies industries [4]. The inverters power efficiency to feed the different type of loads of the grid reach the max level and it is due to the increase of inductive load usage. More inductive loads mean more harmonics and less conversion efficiency [5]. Improvement of the output power quality of the inverter required reducing its total harmonic distortion (THD) content and decrease the size of the filter used [6]. As a solution for this requirement, a new family of the inverter has emerged and known as the multilevel inverter [7]. Multilevel Inverter (MLI) technology assures some advantages comparably to the conventional technology and deals with higher power applications which make it much easier to deal with lower power applications such as the PV systems [8][9][10][11][12][13][14][15][16][17][18][19]. One of the main advantages of the MLI structure is the improvement of the output voltage waveform by approaching the sinusoidal waveform which implicates reducing the harmonic stress

Energy Management in Current Fed Switched Inverter Based Propulsion Motor for Marine Application

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