Compact Three Phase Multilevel Inverter for Low and Medium Power Photovoltaic Systems

Abstract

A new three phase multilevel inverter with reduced number of components count is proposed in this paper. This inverter is designed using a single DC source per phase to generate multiple level output voltage which makes it suitable for low and medium voltage applications, including ac-coupled renewables or energy storages. A generalized circuit configuration is shown in this paper following which the number of output voltage level can be increased as per expectation. Although, each element endures the voltage stress equivalent to the input DC voltage, the value of total standing voltage (TSV) is reduced by the utilization of minimized number of components with respect to the number of series connected capacitors. Further, staircase modulation scheme is used to generate the switching signals. Hence, the proposed inverter can be operated at low switching frequency with optimal output current harmonic distortion which decreases switching losses and suppresses power factor falling. In order to validate the theoretical explanations and practical performances of the proposed inverter, the hypothesis is simulated for 9, 13 and 39 output voltage level inverters for three phase with a line voltage total harmonic distortion (THD) of 6.06%, 4.16% and 2.10% respectively in MATLAB/Simulink and a 5-level single phase laboratory prototype is implemented in the laboratory. INDEX TERMS Pulse width modulation inverters, multilevel inverters, total harmonic distortion, total standing voltage, photovoltaic systems, energy storage.

A Survey on Reduced Switch Count Multilevel Inverters

“…Output varies from ±+9nE for 'n' units. V. FUTURE TRENDS Although, many RSC-MLI topologies are reported in open-loop with RL load, a few RSC-MLI configurations are reported for specific applications such as PV [167][168][169], adjustable speed drives [170][171][172][173], power quality [174], FACTS [175], solid-state transformers [176], energy storage [177,178], electric vehicles [179], wireless power transfer [180] and power factor correction [181,182]. While, the RSC-MLI topologies are widely popular in academia from the past decade, they are yet to be penetrated in commercial applications.…”

A Compact and Cost Efficient Multiconverter for Multipurpose Applications

“…The conduction losses within a system are caused by the parasitic impedances of the circuit elements including the internal on-state resistances of the switches (R sw_on ) and the diodes (R D_on ). Thus, the conduction losses occurred by the parasitic resistances of the switches and diodes can be calculated using the following equations [37],…”

Design of nine step switched capacitor multilevel inverter and its cascaded extension

“…In addition, sensors are required to attain voltage balance among the capacitors 16 . Recent literature shows the development of converter topologies like T type, Hybrid MLI, 17 Active Neutral Point Clamped (ANPC) inverter, 18,19 and SCMLI 20 by modifying the structures of classical topologies to increase the number of levels, reduce the switch count, and achieve inherent capacitor voltage balancing and voltage boosting. Several hybrid multilevel inverter topologies like Flying Capacitor–Cascaded H Bridge (FC‐CHB), Neutral Point Clamped–Cascaded H Bridge (NPC‐CHB), and Neutral Point Clamped–Flying Capacitor (NPC‐FC) 21–24 developed by combining traditional topologies have not been proved useful for low and medium power application.…”