An Original Hybrid Multilevel DC-AC Converter Using Single-Double Source Unit for Medium Voltage Applications: Hardware Implementation and Investigation

Abstract

In this article, an original hybrid multilevel DC-AC converter configurations are proposed by using single-double source unit for medium voltage applications. The proposed topologies are derived by hybridization of single and double source units with polarity changer and cascaded with full-bridge converter for medium and high voltage applications. Two different hybrid topologies presented and each topology configured for both symmetric and asymmetric method. The proposed hybrid topologies compared with the conventional cascaded H-bridge converter (CHB), and the best topologies recommended for medium voltage applications. The comparison in terms of the number of switches, gate driver circuits, maximum blocking voltage by switches and total peak inverse voltages of switches presented. The proposed topologies require a small installation area and low cost. The validity of the proposed hybrid converter structures is verified by simulation using MATLAB/Simulink and hardware results. The simulation and hardware results show a good agreement with the theoretical approach.INDEX TERMS Harmonics distortion, multilevel converters, hybrid converter topology, power switches, symmetric and asymmetric inverter.

A Multilevel Inverter Topology Using Diode Half-Bridge Circuit with Reduced Power Component

“…It is clearly obvious that the cost of the asymmetric topology (CDHB 2 ) is considerably less than the other topologies. Further, in Table 4, recent multilevel inverter topologies [27][28][29][30] are compared with the proposed topology. However, the front-end converter is not considered for the cost comparison because the front-end converter is most required and common to all the topologies for voltage regulation.…”

“…A high number of IGBTs was required because unidirectional switches are used. In [23][24][25][26][27][28][29][30][31][32][33], the bidirectional switches are replaced with a diode and series-connected unidirectional IGBTs. In [23][24][25], the topologies are proposed with cascaded structure and optimal topology to determine the minimum number of power components against the number of voltage levels.…”

“…However, the number of power electronics components and blocking voltage on switches is increasing. Further, topologies [26][27][28][29][30][31][32][33] have recently been published and these topologies are generating a higher number of voltage levels, but the stress on the switch, the number of power components, and dc sources are increasing as the number of levels increases. The modular multilevel converter (MMC) [34][35][36][37] is quite famous for high voltage applications.…”

New Asymmetrical Modular Multilevel Inverter Topology With Reduced Number of Switches

“…This configuration's main benefit is using lesser active and passive components to achieve high output levels. Many topologies are recently developed based on the optimal utilization of unequal dc sources by the least number of power components [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30].…”

“…The structures developed in [11][12][13][14][15][16] have used the Hbridge inverters as a polarity changer to obtain the output terminal's voltage waveform. However, the total standing voltage is high due to the utilization of the H-bridge.…”