A New Cascaded Multilevel Inverter Topology with Galvanic Isolation

Abstract

This paper presents a new compact three-phase cascaded multilevel inverter (CMLI) topology with reduced device count and high frequency magnetic link. The proposed topology overcomes the predominant limitation of separate DC power supplies, which CMLI always require. The high frequency magnetic link also provides a galvanic isolation between the input and output sides of the inverter, which is essential for various grid-connected applications. The proposed topology utilizes an asymmetric inverter configuration that consists of cascaded H-bridge cells and a conventional threephase two-level inverter. A toroidal core is employed for the high frequency magnetic link to ensure compact size and highpower density. Compared with counterpart CMLI topologies available in the literatures, the proposed inverter has the advantage of utilizing the least number of power electronic components without compromising the overall performance, particularly when a high number of output voltage levels is required. The feasibility of the proposed inverter is confirmed through extensive simulation and experimentally validated studies.

Single‐phase boost DC‐link integrated cascaded multilevel inverter for PV applications

“…From (15) and (16), the characteristics of L B1 and L B2 as a function of R o for 9-level and 13-level operations with f s of 10, 30 and 50 kHz are illustrated in Figs. 8a and 9a, respectively.…”

“…8a and 9a that for a particular power rating, the inductor size decreases with an increase in the switching frequency. From (10), (15) and (16), the minimum capacitances C 1 min and C 2 min of C 1 and C 2 required to limit ripple voltage to ΔV c1 and ΔV c2 , respectively, are given as follows:…”

“…In recent times, several boost derived MLIs are reported using boost converter [12], Z-source network [13,14], coupled inductor [15] and switched capacitor (SC) [16][17][18] techniques. Z-source network and coupled inductor-based step-up MLIs provide high voltage gains owing to high switching stress and losses, while SCMLI topologies provide high efficiencies but require large capacitor size and switch count.…”

Review and re‐evaluation of modulation techniques for neutral‐point‐clamped inverters with high‐order filters

“…According to [1][2][3][4], multilevel inverters build the desired output voltage with more discrete voltage levels than conventional twolevel inverters, which can hence attenuate the distortions caused by switching actions greatly. According to their infrastructure, four main categories can be sorted as (i) cascaded multilevel inverter [1], (ii) flying-capacitor multilevel inverter [2], (iii) modular multilevel inverter [3], and (iv) diode-clamped multilevel inverter [4]. Generally, the complexity of the multilevel inverter rises with the total voltage levels that it is able to generate, regardless of the differences of the topologies.…”

A Novel Switched Capacitor Boost Derived Multilevel Hybrid Converter Modeling and Analysis

“…Compared to neural point clamped MLI and flying capacitor MLI, the cascaded configuration uses lesser number of devices for an increase in number of levels [4][5]. Nowadays researchers mainly focus on the design of reduced switch cascaded MLI [6] and hybrid MLI [7] topologies to extract the higher number of output voltage levels. Boost derived multilevel hybrid converter is one of the hybrid MLI proposed in [8] which produces multilevel ac output along with dc output.…”