Reduced switch multilevel inverter topologies for renewable energy sources

This article proposes two generalized multilevel inverter configurations that reduce the number of switching devices, isolated DC sources, and total standing voltage on power switches, making them suitable for renewable energy sources. The main topology is a multilevel inverter that handles two isolated DC sources with ten power switches to create 25 voltage levels. Based on the main proposed topology, two generalized multilevel inverters are introduced to provide flexibility in the design and to minimize the number of elements. The optimal topologies for both extensive multilevel inverters are derived from different design objectives such as minimizing the number of elements (gate drivers, DC sources), achieving a large number of levels, and minimizing the total standing voltage. The main advantages of the proposed topologies are a reduced number of elements compared to those required by other existing multilevel inverter topologies. The power loss analysis and standalone PV application of the proposed topologies are discussed. Experimental results are presented for the proposed topology to demonstrate its correct operation. © 2013 IEEE

A Reduced Single-Phase Switched-Diode Cascaded Multilevel Inverter

The cascaded multilevel inverters (MLIs) are suitable topologies when a high number of voltage levels are needed. Nonetheless, cascaded topologies possess the main drawback of a high number of power switches and gate drivers that make sophisticated control, reducing efficiency, and increasing cost. This article proposes a new fundamental switched-diode topology that is capable of generating five positive-voltage levels with only three power switches, three power diodes, and three dc voltage sources. Based on a combination of the n number of new fundamental topology, two cascaded topologies are proposed, which increases the number of voltage levels and decreases the number of power switches and voltage stress. The proposed cascaded topologies can operate in asymmetric dc sources, so different dc voltage source magnitudes are submitted to minimize the number of components. The main advantages of the proposed cascaded topologies are reducing the number of power switches, and gate drivers with reasonable dc voltage sources count in comparison with other state-of-the-art cascaded topologies. Furthermore, the proposed topologies reduce the cost in comparison with other recent MLI topologies. The power loss analysis and the recommended application for the proposed topologies are discussed. The simulation and experimental works are presented to verify the operation correctness of the proposed topologies

A Switched-DC Source Sub-Module Multilevel Inverter Topology for Renewable Energy Source Applications

This article presents a sub-module topology for switched DC source cascaded multilevel inverter configurations that require fewer switching devices and can generate a high number of voltage levels that are suitable for renewable energy sources. The proposed sub-module topology comprises eight semiconductor switches and four DC voltage sources that generate fifteen voltage levels. Furthermore, the cascaded topology is presented to increase the output voltage levels and to minimize the number of components. The proposed sub-module inverter and its cascaded topology are compared with several multilevel inverters to indicate the advantages and drawbacks of the proposal. The comparison studies show that the proposed topologies require fewer switching devices and gate drivers in comparison with other multilevel inverter topologies. In addition, the proposed cascaded topology reduces the cost of the inverter when compared to other multilevel inverter configurations. Furthermore, the power loss calculations and the implementation of the proposed topology in grid-connected photovoltaic applications are simulated and analyzed. Finally, the performance of the proposal is verified by simulation and experimental results for both symmetric and asymmetric sub-module topologies as well as for the proposed cascaded topology

Model Predictive Control for Single-Phase Switched-Capacitor Multilevel Inverters

Single-phase switched-capacitor multilevel inverters are an excellent alternative for low-power applications as they provide high voltage gain. However, their control and modulation are not simple due to the particularity of these topologies. Finite Control-Set Model Predictive Control (FCS-MPC) has therefore emerged as an attractive control alternative for these inverters. This article seeks to establish guidelines for the implementation of FCS-MPC in this type of inverter. To that end, FCS-MPC is implemented in two topologies that have previously been described in the literature as well as in a new topology. The results establish excellent methodological guidelines for applying FCS-MPC in this family of inverters, that achieve high dynamic responses