Multilevel inverters (MLIs) have gained wide attention in industry and academia to provide higher voltage levels with lower harmonics, power losses, and cost. This study proposes a new asymmetrical MLI topology with reduced component count (RCC). The proposed topology can be extended in a three-phase structure and both modular and cascaded configurations to generate the required number of voltage levels for high-voltage applications. To minimize the power losses and the voltage stress on the switches, this configuration has the potential to produce negative polarity without an H-bridge configuration, thereby the active switches are reduced to only three switches in the conduction path. Due to the possibility of applying different switching patterns, this paper proposes a new solution by employing particle swarm optimization (PSO) algorithm to determine the optimized DC sources’ magnitude. To improve the voltage quality and minimize the total harmonic distortion (THD), the optimal switching angle (OSA) modulation technique is applied to determine the optimum switching angles by PSO algorithm. Moreover, the proposed topology’s effectiveness compared to the conventional cascaded H-bridge (CHB) MLI with 15-levels is illustrated by providing comparative results that express fewer power losses. Finally, the proposed topology’s feasibility and its optimization approach are validated by a single-phase prototype utilizing 15- and 25-levels.

A Single-Phase Reduced Component Count Asymmetrical Multilevel Inverter Topology

A switched-capacitor multilevel inverter topology employing a novel variable structure nearest-level modulation

Boost action is required for enhancing the output voltage of the sources such as photovoltaic (PV) sources, fuel cells, and battery storage devices, which eliminates the need for additional units. For this purpose, switched-capacitor (SC)-based multilevel inverters (SC-MLIs) are widely used. The proposed SC-based single-phase MLI is able to produce 13-level output ac voltage and furnishes voltage gains of 3 and 6. The same topology is also able to produce a single-phase nine-level ac output with a voltage gain of 4. The abovementioned voltage levels and voltage gains are achieved using the proposed topology just by modifying the switching strategy used for firing the switches and do not require any modification in the proposed SC-MLI structure. The proposed configuration of single-phase MLI requires less switch count to produce 9- and 13-level ac output voltages with the abovementioned voltage gains. The switches connected in the proposed configuration undergo less voltage stress compared to the MLIs suggested in the literature. The comparison of the proposed converter topology with the existing MLIs reported in the literature is included. The validation of the performance of the proposed inverter is carried out using experimental results captured on a low-power laboratory prototype.

A 9- and 13-Level Switched-Capacitor-Based Multilevel Inverter With Enhanced Self-Balanced Capacitor Voltage Capability

Boost action is required for enhancing the output voltage of the sources such as photovoltaic (PV) sources, fuel cells, and battery storage devices, which eliminates the need for additional units. For this purpose, switched-capacitor (SC)-based multilevel inverters (SC-MLIs) are widely used. The proposed SC-based single-phase MLI is able to produce 13-level output ac voltage and furnishes voltage gains of 3 and 6. The same topology is also able to produce a single-phase nine-level ac output with a voltage gain of 4. The abovementioned voltage levels and voltage gains are achieved using the proposed topology just by modifying the switching strategy used for firing the switches and do not require any modification in the proposed SC-MLI structure. The proposed configuration of single-phase MLI requires less switch count to produce 9- and 13-level ac output voltages with the abovementioned voltage gains. The switches connected in the proposed configuration undergo less voltage stress compared to the MLIs suggested in the literature. The comparison of the proposed converter topology with the existing MLIs reported in the literature is included. The validation of the performance of the proposed inverter is carried out using experimental results captured on a low-power laboratory prototype. 

A boost type switched‐capacitor multi‐level inverter for renewable energy sources with Self‐Voltage balancing of capacitors

This paper presents a new grid-connected multilevel boost converter topology. The proposed multilevel boost converter includes several switched-capacitor units along with a developed H-bridge. The capability of voltage boosting, inherent voltage balancing of capacitors, reduction of power electronic elements, and voltage on switches are the merits of proposed topology compared to other topologies. All required mathematical analysis related to the suggested topology is presented. The proposed topology is verified by experimental results for grid-connected applications using model predictive controller.

New Grid-Connected Multilevel Boost Converter Topology with Inherent Capacitors Voltage Balancing Using Model Predictive Controller

Eco-friendly recovery of base and precious metals from waste printed circuit boards by step-wise glycine leaching: Process optimization, kinetics modeling, and comparative life cycle assessment

Ali Yahya Rezaee

Papers

New Grid-Connected Multilevel Boost Converter Topology with Inherent Capacitors Voltage Balancing Using Model Predictive Controller

Eco-friendly recovery of base and precious metals from waste printed circuit boards by step-wise glycine leaching: Process optimization, kinetics modeling, and comparative life cycle assessment