In this paper, a dc to ac converter with the ability of voltage increasing is presented. This inverter is designed in a way that just one dc source is used. Also, by using power storage technique and with combining charged capacitors and dc source in series form, output voltage levels can be increased. This inverter is in a modular structure and has the ability of capacitor's voltage self-balancing. H-bridge inverter was not used at the end of the proposed converter and all elements tolerate a voltage stress equal to the amount of input dc source. This leads to remarkable decrease of total standing voltage and peak inverse voltage. Other advantage of the proposed inverter is its potentiality of performance in high-frequency applications. The modular form of the proposed inverter provides the potentiality of extension to higher voltage levels and eases the maintenance. Moreover, considering to the fact that the stress of all components of the suggested inverter is equal to the input source, the performance in high voltage is added to the characteristics of the proposed inverter. The nine-level structure of the proposed inverter is simulated and laboratory test is carried out for the verification of its performance.

This paper introduces a new module for asymmetrical multilevel inverters with a low number of components. The module is a square combination of two back-to-back T-type inverters and some other switches. A square T-type module produces 17 levels by 12 switches and 4 unequal dc sources (two 3VDC and two 1VDC). Also, it can be extended as a cascade connection in two strategies to achieve more levels. The module and its cascade connection are suitable for the applications in several dc sources systems such as photovoltaic farms, which lead to a modular topology with more voltage levels at higher voltages. Inherent creation of the negative voltage levels without any additional circuit (such as H-bridge circuit) is one of the main features of the proposed module. The low total harmonic distortion of the output voltage/current and low number of semiconductors are among the other advantages of the proposed module. A nearest level control method as a switching technique is used to produce high quality output voltage with lower harmonic contents. Simulations have been performed in MATLAB/Simulink and a prototype is implemented in the Power Electronics Laboratory; both the simulation and experimental results show a good performance.

This paper presents a novel step-up DC to AC converter with only one power supply. These types of converters are suitable for renewable and sustainable energy applications with low input DC sources. The proposed topology has the ability of self-voltage balancing and does not apply end side H-bridge to produce a bipolar staircase waveform. Consequently, switching losses and voltage stress of semiconductor components are reduced to a great extent. A small DC voltage source can be used to achieve a high voltage high quality AC waveform through switching the pre-charged capacitors in series and in parallel. Circuit configuration and its operation principle, capacitors’ charging process, thermal model, capacitances and losses calculations are discussed in details. Moreover, the comparison of the proposed circuit with the other single source multilevel converters shows that the proposed topology reduces the number of circuit elements. Finally, a laboratory9-level prototype is built to verify the theoretical analyses and feasibility of the proposed topology. The experimental results show that the converter efficiency at 1 KW output power is 92.75%.

This paper proposes a new single-phase five-level converter based on switched capacitor technique. The capacitor charging in the proposed converter is carried out in a self-balancing form which does not need closed-loop modulations or additional balancing circuits. The proposed topology is a voltage booster without using end side H-bridge for changing load voltage polarity. So, switching losses and total voltage stress of semiconductor components reduce in the proposed converter. The performing modes of the proposed topology, its modulation scheme, capacitors’ balancing analysis, capacitance and loss calculations, and also the development of the proposed converter for enhancing the quality of output voltage waveform are discussed in depth. Moreover, the comparison of the proposed structure with the other multi-level topologies shows that the proposed converter can reduce the number of semiconductor elements and the required isolated DC sources. Finally, the simulation and experimental results validate the appropriate performance of the proposed converter.

This study presents a new topology of switched‐capacitor (SC) multilevel inverter, which is able to step‐up input DC voltage to a multilevel AC waveform. This single source inverter is designed based on series connection of the capacitors that charged by input DC sources through a SC network. The proposed modular inverter uses famous T and cross‐connected modules that can be simply extended to higher output voltages without increasing the amount of total standing voltage and peak inverse voltage of switches. It generates positive and negative voltage levels inherently, which eliminates requirements of H‐bridge inverters that are traditionally used to achieve a bipolar output voltage. Analysis shows that the voltage stress on components, cost, efficiency and losses are kept in acceptable range especially for higher‐voltage levels. Capacitor's voltage self‐balancing is another inherent advantage of this modular topology which leads to simplify control strategy and eliminate excess balancing circuit. Performance of a six‐step proposed structure is evaluated by theoretical analysis, simulation and experimental results.

This study presents a new module for multilevel inverters with reduced components. Each module produces 25 levels using four asymmetrical DC voltage sources (two 1 V _DC and two 5 V _DC sources) and 10 semiconductor switches. A significant advantage of the suggested module is its potentiality in producing voltage levels with negative polarity without any end side H‐bridge inverter. Therefore, switches with lower voltage ratings are used in its structure. Series connection of the proposed structure leads to a modular topology which produces more voltage levels using reasonable number of switches, gate driver circuits, power diodes and less DC voltage sources. These advantages are analysed by comparing this structure with other state‐of‐the‐art topologies. Selective harmonic elimination pulse width modulation (SHE‐PWM) scheme is used to achieve output voltage with high quality. To produce all voltage levels, two algorithms are proposed to determine DC voltage sources magnitude. The accuracy of the suggested module performance in producing all voltage levels is verified by simulation and experimental results.