A new structure of single‐phase two‐stage hybrid transformerless multilevel PV inverter

Abstract

Transformerless inverters are becoming popular for grid-connected photovoltaic applications due to their simplicity, reduced size, weight, cost, and higher efficiency. In this paper, a two-stage hybrid transformerless multilevel inverter (MLI) for single-phase grid-connected photovoltaic power generation system (PVPGS) is presented. The proposed topology comprises a multilevel boost converter (MLBC) and a symmetrical hybrid MLI. MLBC combines the boosting and switched capacitor voltage functions to produce self-balanced multiple voltage levels. The proposed MLI is derived from a combination of bidirectional switches, a half bridge, and a diode-clamped branch, which can produce only two variations in the total common mode voltage and is capable of suppressing leakage current as per DIN VDE 0126-1-1 grid standards. It offers the advantages of scalability, reactive power capability, reduced total harmonic distortion, and filter size. The proposed hybrid transformerless seven-level inverter is simulated in MATLAB, and experimental setup is built to validate the effectiveness of the proposed configuration. Finally, a comprehensive comparison is made with other seven-level inverter topologies.

A new structure of three‐phase five‐level inverter with nested two‐level cells

“…Figure depicts the measured efficiency comparison of the proposed nested 5L inverter with NTT‐5L inverter. The efficiency curves are evaluated in PSIM using discrete IGBT thermal modules of distinct voltage ratings as per the device stress, at different loading conditions, wherein the maximum power output, m a , and PF are fixed to 3.5 kW, 0.9 and 0.9 lag, respectively. Table lists out the selected IGBT semiconductor devices for efficiency computation.…”

An FPGA‐based switching photovoltaic‐connected inverter topology for leakage current suppression in grid‐connected utilizations

“…PV sources have been recognized as one of the best and most promising renewable energy sources because of their reliability, cleanliness, and free emission features. [1][2][3] According to the European PV industry association and the global PV annual market rules reports, the PV market had around 31-GW energy exchange in 2012, which is four times greater than the reported amount of 2008. It is projected that if this market remains a considerable policy-driven market, it will reach 84 GW in the near future.…”

“…The grid-connected PV inverters should be used in accordance with the grid standards and the applicable laws so as to comply with system protection and operation criteria. [10][11][12][13][14][15][16][17] Electrical factors such as leakage current protection, network frequency monitoring, active and reactive power control, and power quality are among these factors. [18][19][20][21] To this end, the most stringent and accurate standards are announced for PV systems to ensure the safety and reliability requirements of the system.…”

“…Many considerable and industrial models and new structures have only been released and introduced in the last few years. PV sources have been recognized as one of the best and most promising renewable energy sources because of their reliability, cleanliness, and free emission features 1–3 …”

Design and implementation of a novel asymmetrical multilevel inverter optimal hardware components

“…Then, the recommended asymmetrical topology compared with existing topologies; every component calculated for a similar number of voltage levels. While all the existing topologies would require 10 to 16 switches and 4 to 6 DC sources to deliver a 31‐level output voltage, the proposed topology requires only 12 switches and 4 sources with low THD. The drastically reduced requirement of switches in the proposed topology compared with the conventional topology to produce better results makes it more desirable for a future renewable application.…”