Symmetrical Hybrid Multilevel DC–AC Converters With Reduced Number of Insulated DC Supplies

Abstract

Novel symmetric hybrid multilevel topologies are introduced for both single-and three-phase medium-voltage highpower systems. The topology conception is presented in detail, where a three-level switching cell with low component count, and its modulation pattern give the origin of the proposed converters. Voltage sharing and low output-voltage distortion are achieved. The theoretical frequency spectra are derived. Switching devices are separated into high-and low-frequency devices, generating hybrid converters. Five-level three-phase topologies are generated from only three insulated dc sources, while the number of semiconductors is the same as for the cascaded H bridge. Both simulation and experimental results are provided showing the validity of the analysis.

Analysis and Comparison of Pd, Pod, Apod PWM Techniques for Symmetrical Multilevel Inverter

“…Figure. The inverter shown in Figure 1(a) is a five level singe phase inverter where, all switches operate with high frequency. In cascaded H-bridge multilevel inverter output voltage is given by 2N+1 [11] , [12] similarly, output voltage for SMLI can be obtained by expression 2N + 1 where N is the Number of DC sources [9] Table 1 is shown to explain how the staircase voltage is synthesized across the load AN. The five-level phase-leg "a" output with respect to the neutral point "n", V an can be obtained by following switching combinations.…”

“…Cascade multilevel inverter are further subdivided into hybrid/non-hybrids and symmetrical/asymmetrical type topology. Symmetrical multilevel inverters are inverters with symmetrical DC sources [3], [4], [5], [6]. This paper presents a performance analysis of five level inverter with reduced isolated DC source and PD, POD& APOD PWM control techniques is discussed.…”

“…SMLI topology are generate nine level line voltage and five level phase voltage. As compared with a HBridge Cascaded multilevel inverter, the number of isolated DC source are reduced in the SMLI [6], but, the number of semiconductor device remain the same [7], [8], [9], [10].furthermore by reducing the number of isolated DC sources, the number of cables connecting the input transformer terminals to the rectifying bridges is reduced. In this paper, a MATLAB/Simulink analysis and compared thefive level output phase voltageTHD between the PD, POD and APOD PWM techniques for symmetrical multilevel inverter.…”

Multilevel Inverters Power Topologies and Voltage Quality: A Literature Review

“…A symmetrical hybrid multilevel converter with reduced number of insulated DC sources is proposed in [52]. This topology is a combination between the NPC and H-bridge inverter, Fig.…”

A Novel Concept for Three-Phase Cascaded Multilevel Inverter Topologies

“…Although several topologies have been proposed in the literature in order to reduce the device count and increase the number of levels in the output voltage of single phase CMLIs, the majority of these topologies have not been extended to three-phase structure yet. It is a common trend that the number of components of single phase topologies is tripled when they are extended to three-phase structures [13,14,[26][27][28].…”