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This paper introduces a new structure of a multi-level inverter (MLI) to generate high-level AC voltages using a low number of switches with a quasi-sine waveform. The small number of driver circuits utilised in bidirectional switches is a salient characteristic of this inverter. Also, the number of conducting switches at each voltage level is low in this structure. This results in lower conduction losses of the switches. The proposed topology can be used as the cascaded structure with different approaches to select the value of voltage sources. Power losses are discussed for the proposed structure. To compare the proposed multi-level inverter and demonstrate its superiority, a comparison has been made with some recently presented topologies. According to the comparison results, the advantage of the proposed structure is producing high voltage levels with a smaller number of switches and driver circuits. To prove the suitable performance of the proposed MLI, a 21-level symmetric and 37-level asymmetric inverter containing 14 switches are designed and simulated in the MATLAB/Simulink program. A laboratory prototype for each of these inverters is implemented. The experimental results finely verify the simulations. Besides, an accurate comparison with recently introduced multilevel inverters has been carried out to confirm the effectiveness and superiority of the proposed structure. [ABSTRACT FROM AUTHOR]

In this brief, a new switched capacitor-based structure is presented for a single-phase multilevel inverter. The proposed structure is capable of boosting the input voltage and producing fifteen voltage levels at the output utilizing two separated DC voltage sources along with a switched capacitor unit. The proposed structure also has self-charging capability and can automatically adjust the capacitor voltage without any sensor. A quantitative comparison with similar structures has been performed to confirm the proposed structure. Furthermore, loss and thermal simulations have been performed for the proposed structure. The functionality of the proposed structure is examined by the simulation results. Finally, a laboratory prototype is implemented to verify the effectiveness and accuracy of the proposed structure and its control method. [ABSTRACT FROM AUTHOR]

To meet the higher DC link voltage requirement in distributed energy resources (DERs) such as fuel cells (FCs), wind turbines (WTs), and photovoltaic (PV) systems, DC–DC converters are applied. A voltage‐lift (VL) circuit‐based transformer‐less active switched LC‐network (ASLC) converter with a high‐voltage gain is proposed in this paper. Compared to a similar reference converter, the voltage gain of the proposed converter increases efficiently by adding one extra capacitor and diode. The operation of the converter in continuous current mode (CCM) and discontinuous current mode (DCM), the analysis of the steady‐state condition, and comparative analysis with some similar converters are discussed. Moreover, the parasitic elements are assumed to calculate the DC‐voltage gain and the efficiency of the converter accurately. The performance of the proposed step‐up converter is simulated in the PSIM software. A prototype circuit rating of about 20/280 V, 200 W of converter model is designed, and its performance is validated. The experimental outcomes clarify the feasibility of the proposed converter. [ABSTRACT FROM AUTHOR]

Multi‐level inverters (MLIs) for medium or high power and voltage utilization have acceptable application in industry and are utilized commercially. The performance of MLIs is considerably preferable to traditional two‐level inverters due to their negligible harmonic content, small filter size, utilization of lower‐rated voltage devices, low electromagnetic interference (EMI), and so on. However, in the face of these many advantages, few disadvantages can be expressed such as more device count and a sophisticated control strategy. This paper presents an improved switched‐ladder topology to enhance the performance of multi‐level inverters by improving the above drawbacks. Compared to existing inverter topologies, the proposed extendable diode‐containing bidirectional structure requires fewer switches and driver circuits. The proposed topology is compared with other similar topologies, and its superiority is examined. Fundamental switching frequency modulation technique is utilized to obtain high‐quality output voltage waveforms with lower harmonic contents and reduced switching losses. This converter, despite the use of diodes, can supply the low power factor inductive‐resistive loads, bidirectionally. To demonstrate the performance of the proposed topology, in addition to simulation with the nearest level modulation technique, a prototype of the proposed structure has been implemented and tested. The results display the proper performance of the proposed topology in the real‐time environment. [ABSTRACT FROM AUTHOR]

Multilevel inverters are a new generation of DC–AC converters at medium and high voltage and power levels. In this paper, a new single-phase cascaded multilevel inverter is presented. For this purpose, a new basic cell is presented at first. Then, the new multilevel inverter structure is yielded by series connection of these cells. The proposed new cell is only capable of generating positive voltage levels, and therefore, to produce zero and negative voltage levels, the proposed structure is constructed based on H-bridge module. In order to reduce the maximum blocking voltage especially on H-bridge switches, the cascaded connection of the proposed converter is investigated. A comprehensive comparison is carried out between the proposed multilevel inverter with the classical and recently introduced structures in terms of the number of switching devices, the number of drivers, the total blocking voltage of the switches as well as the loss and efficiency. The accuracy of the proposed inverter's performance is simulated in MATLAB/Simulink in symmetric and asymmetric topologies for a 17-level and 23-level output voltage respectively, and then evaluated by the laboratory prototype. [ABSTRACT FROM AUTHOR]

Summary: In this paper, a bidirectional diode containing multilevel inverter is introduced to reduce the number of switching elements especially in the case of a high number of output voltage levels. In comparison with classic and recently introduced symmetrical topologies, which are trying to reduce the switch count, this topology has a lower number of semiconductor switches in the same number of output voltage levels. This makes the proposed inverter to be a suitable choice for medium voltage applications like renewable energy applications as well as medium voltage electric drives. Moreover, it can be used in a cascaded configuration for high voltage levels. To depict the performance of the proposed structure, a comprehensive comparison is made between this topology and classic and recently proposed symmetric topologies in terms of switch and gate driver count, power losses, and cost. The performance of the proposed symmetrical 11‐level converter is analyzed and simulated in MATLAB/Simulink for both PWM and selective harmonic elimination switching methods. Not only the results are desirable but also the experimental results of laboratory prototype validate the simulation results. [ABSTRACT FROM AUTHOR]