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Multilevel voltage source inverters/converters (ML-VSIs) with an integrated voltage-boosting feature have been popular in recent years as an interface between the provided low-magnitude DC voltage and standard 220V rms grid voltage. The voltage-boosting feature is achieved with an integrated switched-capacitor (SC) or a switched-boost (SB) technique, while the circuit configuration of the resulting ML-VSIs can be based on a standard half-bridge-based design or a common-ground/midpoint-clamp-based structure. The critical challenges for SC-based ML-VSIs are the discontinuous nature of the input current, pulsating current stress over devices, and the static ratio of the voltage-conversion gain. These challenges require that researchers go through either a two-stage-based boost-integrated design with a front-end DC–DC boost converter or a single-stage SB-based ML-VSI with inherent dynamic voltage-conversion gain. This chapter investigates the state-of-the-art contributions of boost-integrated ML-VSIs and provides insights for overcoming critical challenges like excessive current stress and the inrush current problem. The chapter also outlines the relatively new concept of SB-based MLIs, while the working principles of several recently proposed structures are reviewed and compared.

Multilevel inverters (MLIs) with a common-ground (CG) circuit design and a switched-boost (SB) technique are of interest in transformerless grid-connected applications due to the enhanced overall efficiency, higher power density and reduced leakage current concern. Utilization of the SB technique in MLIs leads to obtaining a single-stage power conversion platform with a dynamic voltage boosting feature. Drawing a continuous input current and spike-free current stress of the devices are two additional features of SB-based MLIs. Regarding the current state-of-the-art contributions, an interleaved CGSB-based MLI is introduced in this work. The main benefits of the proposed topology are larger injected grid current handling capability with a reduced current stress, uniform peak voltage stress across the devices, bidirectional power flow operation, controllable power sharing, and generalization capability to realize any number of output voltage levels. Through a modular design with a phase-shifted PWM technique, the injected grid current is shared among the modules, while the size of the grid-interface filters is reduced, leading to establishing a practical design with enhanced overall efficiency. The working principle of the proposed converter is discussed in detail. Design guidance, comparative study and extensive closed-loop experimental results obtained from a 5.1 kW grid-tied laboratory-built prototype are then given to validate the feasibility and performance of the proposed solution.

Multilevel inverters with common-ground feature have been getting attention especially for grid-tied photovoltaic systems. These inverters have the grid neutral line connected to the negative pole of the dc bus, eliminating the common-mode leakage current which is a critical issue in grid-connected PV systems. This paper proposes a common-ground five-level transformerless inverter with a reduced switch count for solar photovoltaic applications. The proposed inverter comprises only four power switches, three diodes, two capacitors and two inductors. Moreover, only two switches operate at high-frequency, enabling the reduction of switching losses. The interleaved operation of a coupled inductor enhances the quality of the output current, as the first group of harmonic components is around twice the switching frequency. Additionally, a full dc- bus voltage utilization is provided and the reactive power capability is achieved. The paper details the operation modes, the design guidelines as well as a control and modulation strategy for the proper operation of the inverter. Finally, experimental results are obtained to validate the performance of the proposed grid-tied inverter.

In this article a new bridgeless BL buck boost power factor correction PFC converter using pulsewidth modulation PWM control is presented The introduced structure operates in a discontinuous conduction mode DCM to achieve the sinusoidal form of the input current inherently The proposed converter utilizes a simple zero voltage transition ZVT circuit in which the auxiliary switch is turned on and off under zero current switching ZCS condition and the main switches turn on and off under zero voltage switching ZVS Moreover all diodes are turned off under ZCS conditions and the reverse recovery problem is solved By reducing the number of semiconductor elements in the current flow path conduction loss is minimized Also the proposed structure utilizes only one magnetic element The above mentioned advantages along with a low total harmonic distortion THD and high efficiency are the main benefits of the proposed structure compared to previous topologies In addition unlike the BL buck converter the input current dead angle is omitted without adding any extra components Finally a 500 W 100 kHz prototype at 90 265 Vrms input and 96 V output is implemented to verify the theoretical analysis and it illustrates the efficiency of 97 35 and the input current THD is about 2 7 at 220 Vrms input voltage

Distributed generation systems integrated into the modern electrical grid demand novel circuit architectures that can combine high efficiency and high power density together. The transformerless highly efficient and reliable inverter concept (HERIC) topologies are notable due to their mitigated leakage current concerns, constant common-mode voltage, and high efficiency. Nonetheless, the HERIC-based structures feature a maximum of three-level ac output voltage, forcing the conversion system to integrate large output filters to meet the grid codes. This article introduces a novel HERIC active-clamped converter with bidirectional power flow and full reactive power capabilities that can achieve five-level output voltage. This is accomplished by means of a phase-shifted pulsewidth modulation technique that effectively doubles the apparent switching frequency of the inverter and improves the quality of the injected ac power. Consequently, the topology can achieve higher power conversion efficiency, while using the same or a smaller output filter. To verify the feasibility of the proposed converter, a 2.5-kW SiC-based prototype was built and tested in the laboratory under different operation conditions.

Grid-connected inverters with a multilevel output voltage and an integrated dynamic voltage boosting feature are promising to achieve higher overall efficiency/power density, reduced output filter size, and better power quality. However, the input current of such a single-stage system might be pulsating with low- and high-frequency ripple contents in a single-phase grid-connected application. To tackle this challenge, active power decoupling (APD) can be used to keep the input current flat and reduce the current stress of the devices with an efficient performance. On the other hand, the grid voltage is usually nonideal in practice, polluted with the harmonics. This causes additional complexity in the closed-loop control system to maintain the injected power quality. The aim of this article is to apply a tailored closed-loop APD control on a recently proposed single-source single-stage switched-boost (SB) five-level converter leading to further enhancing its overall efficiency without adding any extra circuit components. A distinctive feature of the proposed solution is using a single proportional-resonant controller with a filtered feedforward term to achieve APD, even under a distorted grid voltage condition. This solution can also be applied to other single-stage SB-based converters as long as their input current before integration of the APD control contains a low-frequency ripple content. A 2-kW SiC-based prototype is built to validate the feasibility and accurate performance of the proposed method via experiments when connected to a grid with harmonic pollution.

This paper proposes two single-phase boost inverters that are capable of mitigating the high-frequency common-mode voltage (CMV). The conventional two-stage topology that consists of a frontend boost converter and a backend H-bridge inverter is restructured. While retaining the advantages of the conventional topology such as continuous input current and dynamic voltage gain, the proposed 3-level boost inverter achieves constant CMV without requiring any additional components. An extended 5-level boost inverter is also proposed by integrating another capacitor controlled by 4 switches to the 3-level topology. For the same inductor charging duty-cycle and inverter modulation index, the voltage gain of the proposed 5-level boost inverter is double compared to the 3-level counterpart. The operation of the proposed 3-level and 5-level boost inverters is comprehensively analyzed and verified by simulation results.

The latest single-stage boost inverter has many advantages such as continuous input or dc source current, high-frequency common-mode voltage mitigation and generation of three-level boosted ac voltage. However, it requires a dedicated circuit design, which cannot be implemented using commercial power modules such as half-bridge. To resolve this drawback, this letter proposes an improved topology designed using three half-bridges. While retaining the advantages of the latest boost inverter, the proposed topology reduces the number of conducting switches for load current during positive voltage level that enhances efficiency. The proposed three-level boost inverter can be extended to generate five levels by merely adding a half-bridge and a capacitor. The derivation of the proposed single-stage boost inverters and their operation are analyzed. Simulation and experimental results are presented for verification.

This paper proposes two novel 5-level active neutral-point-clamped (ANPC) inverters that double the voltage gain of the conventional topology from half to unity. Each phase of the proposed topologies is constituted by three half-bridges that control a flying capacitor to generate 5 symmetrical ac voltage levels. The natural voltage balancing of dc-link and flying capacitors in the proposed topologies implies that the sensors and voltage balancing controller commonly used in the conventional ANPC inverter are no longer necessary. In addition to switch count reduction, the most noteworthy merit of the proposed topology is its ease of implementation with commercial half-bridge modules, where the design of dedicated circuit is not needed. The operation of the proposed 5-level unity-gain ANPC (5L-UG-ANPC) inverters is analyzed and validated through simulation and experimental tests.

Active neutral point-clamped (ANPC) multilevel converters with integrated flying-capacitor (FC) technique are widely used in many industrial applications owing to their low losses, reduced stress on devices, bidirectional operation, and leakage current attenuation capability. Their major setback related to the half dc-link voltage utilization at the ac output has also recently been addressed using the concept of active boost neutral point-clamped (ABNPC) converters with a switched-capacitor (SC) technique. Nonetheless, such a voltage-boosting capability in ABNPCs causes an excessive voltage stress on devices, when the provided dc-link voltage is larger than double of the grid peak voltage. To address this critical challenge, the concept of dual-mode (DM) converter that can retain the quality of ac output with a reduced voltage stress on devices over a wide range of the input dc voltage is introduced. Following this concept, a family of three DM-ANPC five-level (5L) converters is presented in this article, where they can be operated in either buck or boost mode. This allows to operate the converters with a wide range of input dc voltage utilization and an improved performance. Each of the proposed DM-ANPC-5L converters requires 10 power switches, while they offer a bidirectional power flow feature with an integrated FC and/or SC technique. Extensive analysis, comparative study, and several simulation and experimental results obtained from a laboratory-built prototype operating in the grid-connected condition are presented to validate the performance of the proposed converters.

The conventional active neutral-point-clamped (ANPC) multilevel inverters are popular for single-phase applications owing to their advantage of mitigating high-frequency common-mode voltage (CMV). With the ac neutral connected to the midpoint of dc link, their voltage gain is restricted to only half. For boosting output voltage, a two-stage structure by adding a frontend dc-dc boost converter is commonly used. This article investigates the performance of the conventional two-stage 5-level ANPC inverter and proposes an improved topology by splitting the dc-link midpoint and cross clamping them to the dc-link capacitors. While using the same number of power devices and retaining the advantages of the conventional two-stage 5-level ANPC topology, such as high-frequency CMV mitigation and continuous dc source current, the proposed 5-level split-midpoint cross-clamped (5L-SMCC) inverter achieves several advantages, such as higher voltage gain, lower voltage across dc-link capacitors, lower inverter voltage stress, and natural voltage balancing for all capacitors without requiring any balancing controller or sensor. In addition, it saves one capacitor by eliminating the flying capacitor of the conventional 5-level ANPC inverter. The operation of the proposed 5L-SMCC inverter is thoroughly analyzed. For validation, simulation and experimental results are presented.

Transformerless grid-connected inverters with highly efficient and reliable inverter concept (HERIC) and positive-negative neutral point-clamped (PN-NPC) circuit configurations exhibit excellent performance in terms of overall efficiency, common-mode voltage, and alleviated leakage current concern. These inverters are designed to generate only a three-level (3L) output voltage waveform, thereby reducing the power density of a conversion system. On the other hand, it is well-known that increasing the inverter output voltage levels entails the reduction of the output filter size. In this regard, this article aims to develop a five-level (5L) inverter output voltage for the improved versions of HERIC-clamped and original PN-NPC inverters. This is achieved with either phase-shifted or level-shifted pulse width modulation technique leading to further quality improvement of ac voltage and current waveforms through increasing the number of output voltage levels. Therefore, a much smaller output filter size can be utilized, while the overall efficiency of the entire system is enhanced. Two laboratory-built SiC-based prototypes for both the proposed HERIC-clamped (1.8 kW) and PN-NPC-5L (2 kW) inverters have been fabricated to show the feasibility and effectiveness of the proposed solution via experiments.

In this article, we present a family of multilevel converters with the single-stage dynamic voltage-boosting feature, reduced number of circuit components, modular structure, bidirectional operation, continuous input current, and acceptable overall efficiency. The proposed structure is based on a three-level single-stage boost integrated inverter with an embedded quasi-H-bridge (QHB) cell. It is comprised of five unidirectional power switches and a floating capacitor. By differential connection of two or three QHB cells and with the aim of a single inductor/input dc source, several derived topologies for both the single and three-phase applications with different multilevel output voltage performances have been achieved. The aforementioned advantages make this converter a suitable candidate for renewable energy applications. Theoretical analysis, design consideration, comparative study, and several experimental results for a 3-kW laboratory-built system are presented to validate the effectiveness and feasibility of this proposal.

Multilevel inverters (MLIs) with switched-capacitor (SC) units have been a widely rehearsed research topic in power electronics since the last decade. Inductorless/transformerless operation with voltage-boosting feature and inherent capacitor self-voltage balancing performance with a reduced electromagnetic interference make the SC-MLI an attractive converter over the other available counterparts for various applications. There have been many developed SC-MLI structures recently put forward, where different basic switching techniques are used to generate multiple (discrete) output voltage levels. In general, the priority of the topological development is motivated by the number of output voltage levels, overall voltage gain, and full dc-link voltage utilization, while reducing the component counts and stress on devices for better efficiency and power density. To facilitate the direction of future research in SC-MLIs, this article presents a comprehensive review, critical analysis, and categorization of the existing topologies. Common fundamental units are generalized and summarized with their merits and demerits. Ultimately, major challenges and research directions are outlined leading to the future technology roadmap for more practical applications.

Multilevel inverter demonstrates advantages over conventional topologies to meet the grid codes and standards. Compared to 3-level inverters, multilevel inverter exhibits significantly better harmonic performance, better efficiency, lower filter size, and less dv/dt and di/dt in the switches. In this regard, a modified HERIC-based topology with a 5-level modulation technique is derived from the conventional 3-level passive midpoint clamped HERIC-based topology and introduced in this paper. A circuit description and working principles of the proposed converter with simulation results, and experimental results are given to demonstrate the feasibility of the concept.

Voltage source multilevel inverters with reduced leakage current, single-stage voltage step-up feature, compact design, and an efficient performance are a promising technology for high-frequency ac (HFac) microgrids feeding through renewable energy sources. This article proposes a novel single-source common-grounded (CG) step-up nine-level (9L) inverter, which can be applied in HFac microgrid applications. The proposed CG-based boost inverter is comprised of only nine switches (9S) and three self-balanced capacitors. Using the switched-capacitor (SC) technique, a double voltage boosting feature within a single power processing stage is achieved, while the leakage current concern is eliminated due to a CG-based configuration between the input dc source and the null of the grid. With the help of an LC input filter, the input current profile is free from large discontinuous inrush spikes. The working principles of the proposed 9L9S-CGSC inverter are discussed in this article. The modulation and closed-loop control strategy, as well as a comparative study, are presented. Finally, the open and closed-loop grid-tied performances of the proposed topology are evaluated by both simulation and experimental results obtained from a 1.2-kW laboratory-built prototype.

The circuit performance of conventional active neutral point-clamped (ANPC) inverter is widely accepted in many renewable energy-based applications like photovoltaic (PV) or electric vehicle grid-connected systems. This is mainly because of its excellent characteristics in terms of voltage/current stress profile of the switches, bidirectional power flow capability, and efficient operation. Nonetheless, due to its half-dc link voltage utilization in the ac output voltage, another power processing stage with additional active and passive elements is required to make its output voltage compatible with the grid when low and wide varying input dc source is available. In this paper, a novel ANPC-based five-level (ANPC5L) inverter with a single-stage boost-integrated circuit design is presented. The proposed topology is able to make the peak output voltage of the conventional ANPC5L inverter followed by a front-end bidirectional boost converter double using the same number of power switches but with less total standing voltage across semiconductors. The working principles of the proposed topology is discussed. Experimental results obtained from 1.3 kW laboratory-built prototype under the grid-connected condition are also given to support the discussion.

This paper presents a common-ground five-level transformerless inverter for solar photovoltaic (PV) applications. In the proposed inverter, the grid neutral line is directly connected to the negative pole of the dc bus eliminating the common-mode leakage current which is a critical problem in grid-connected PV systems. Moreover, the proposed inverter has only four power switches, making the first five-level common-ground topology with less than six switches found in the recent literature. In addition to low switch count, only two switches are operating in high-frequency. The operation modes, the design guidelines as well as a modulation strategy are presented. Simulation and experimental results are obtained to demonstrate the performance of the proposed inverter.

Recently, inverters with a common ac and dc ground are gaining significant interests due to their zero common-mode voltage that made them particularly attractive for the solar photovoltaic (PV) application. However, the dc source current of the existing topologies is discontinuous, and their voltage gains are limited. This paper proposes a novel common-ground-type boost inverter that achieves continuous dc source current with significantly enhanced dynamic voltage gain. It consists of one boost inductor, four capacitors, nine power MOSFETs and two power diodes. Voltage-boosting and generation of 9-level ac voltage are achieved concurrently within a single-stage operation. The operation of the proposed CGT-9L-BI inverter is analyzed. Simulation and experimental results are presented for validation.

Single-stage grid-connected PV inverters with a transformerless (TL) concept have been a hot spot research topic in both the academia and industry in the latest years. Dynamic voltage boosting feature through the adjustment of de duty cycle, reduced value of the current and voltage stress across the switches, common-ground (CG)-based circuit architecture and capability of larger number of output voltage levels generation can make these types of inverters an attractive option for an efficient and compact design. In this paper, a novel seven-level (7L)-CG-based TL inverter is proposed, which possesses all the above-mentioned features for a compact design. The working principle and modulation strategy are discussed. Some simulation results are presented to attest a proper performance of the converter.

Switched-capacitor multilevel inverters (SCMLIs) are gaining widespread attention in recent decades due to their simple design, voltage boosting capability, and inherent capacitor voltage balancing feature. However, the advantages offered by SCMLIs come at the cost of employing a higher number of active and passive components and capacitor voltage balancing issues with an inrush current profile. This paper introduces a novel configuration of SCMLIs with a lower number of power components with inherent voltage boost. The basic 5-level topology consists of a single capacitor, an inductor, a diode, and seven active switching elements. To improve the transient response and the inrush current profile of the converter, a soft start and quasi-resonant charging capability has been explored and implemented. Considering the inherent capacitor voltage balancing of the proposed SCMLI, a new finite control set-model predictive control (FCS-MPC) method with a single objective and a less computational burden is also developed, which contributes to injecting a fully controlled current for the grid-connected applications. The proposed topology is compared with other existing five-level inverter topologies to show its superior capabilities/advantages. And finally, the performance of the proposed topology and its associated FCS-MPC mechanism are validated by the measurement results.

Common-ground (CG) string inverters with a transformerless (TL) circuit configuration have been broadly popular in grid-connected photovoltaic (PV) applications. The most important feature of a PV string TL inverter with a CG circuit connection is the elimination of leakage current concerns. Having the voltage boosting property within a single power processing stage can also be propitious to further facilitate the integration of low-scale PV string panels with higher efficiency. An efficient topology of such converters is presented in this study, which is able to produce a five-level stair-case output voltage waveform using an integrated switched-boost (SB) cell with only seven power switches. The proposed SB common grounded five-level (SBCG5L)-TL inverter can also be extended for the three-phase CG-based applications with the contribution of the same integrated SB cell. As for the single-phase configuration, it needs two dc-link capacitors and two power diodes along with two small inductors. A quasi-soft charging operation of the involved capacitors is also achieved. To control the injected current under the grid-connected condition, a single-step model predictive control (MPC) technique with a fixed switching frequency operation has also been presented. The proposed circuit description, the theoretical analysis of the applied MPC principles, and the comparative study with associated experimental results are also presented to ascertain the correctness and feasibility of the proposed SBCG5L-TL inverter.

A single-phase common-ground five-level (5L) inverter with a dynamic voltage conversion gain and capability of operating in a wide input voltage range and a single-stage energy conversion configuration is presented in this article. The proposed topology requires nine active power switches and is comprised of an integrated switched-boost (SB) module connected in series to a switched-flying-capacitor (SFC) cell. Two self-balanced capacitors with a single boost inductor in the integrated SB module are employed to generate a 5L output voltage waveform with a dynamic voltage conversion gain. The current stress profile of all the active and passive elements is kept within a permissible input current range. By adopting an extra diode-capacitor-inductor network into the integrated SB module and with the utilization of the same SFC cell, the proposed topology is extended to achieve a quadratic voltage conversion gain while retaining the quality of ac voltage waveform. Theoretical analysis, closed-loop control/modulation principles, design guidance, comparative study, and relevant experimental results obtained from a 1.5-kW laboratory-built prototype are presented to ascertain the operation and feasibility of the proposed system.

H-bridge inverter is a common topology used for single-phase applications. Due to its limited voltage gain, a two-stage power conversion with a front-end dc-dc converter is usually adopted to accommodate the low dc source voltage. Recently, single-stage boost inverters are gaining significant interest due to their higher power efficiency and compactness. This paper presents a family of boost inverters with continuous dc source current. By the incorporation of merely a power switch and a boost inductor to the first leg of H-bridge, voltage-boosting and 3-level generation can be simultaneously achieved within a single-stage operation. All potential topologies using the same number of components are derived. An extension to generate five voltage levels with voltage gain enhancement is also proposed. The operation of the proposed boost inverters is thoroughly analyzed. Simulation and experimental results are presented for verification.

Recently, an improved version of active boost neural point clamped (ABNPC) inverter with the capability to produce five output voltage levels using only six power switches has been presented in the literature. The presented modulation strategy of such inverter is based on an open-loop voltage-oriented control approach. The major advantage lies in its inherent voltage balancing of the integrated flying capacitor with the leakage current elimination capability for transformerless grid-tied photovoltaic applications. Using a fast and robust current controller-based technique, the injected grid current of the 5L-ABNPC can be tightly controlled under various dynamic conditions of the local grid. The aim of this paper is to apply two improved versions of the Finite Control Set (FCS) and Continues Control Set (CCS)-Model Predictive Control (MPC) strategies to control different operations of the discussed 5L-ABNPC inverter. The proposed solutions present an optimal switching state scheme with less computational burden for FCS-MPC and also a fixed switching frequency spectrum for the CCS-MPC. To verify the correctness of the inverter operation and its control platform, simulation and experimental results are also presented.

Dynamic voltage boosting feature in photovoltaic (PV) grid-integrated application is a necessity to achieve the maximum power point of PV arrays as well as boost the input voltage to the necessary dc-link voltage requirement. Such feature is usually achieved by incorporating a front-end boost or buck-boost dc-dc converter tendem with a conventional two or three-level inverter. However, such an integration cannot efficiently meet many IEEE strict grid codes from the power quality, ground leakage current, and the overall efficiency per power density aspects. The aim of this paper is to present a new five-level (5L) inverter with an integrated single-stage dynamic voltage-boosting concept and a common-grounded (CG) feature. As a result, the concern of ground leakage current is addressed through the provided CG feature, whilst both the power quality and overall efficiency of the system are improved with a 5L single-stage boosted output voltage waveform. To confirm the effectiveness of the proposal, apart from the circuit description, some experimental results are also presented.

Single-source inverters with integrated switched-boost (SB) module and single-stage energy power conversion architecture have become a popular solution in many power electronics applications. This paper presents a novel topology of such types of inverters, which offers a modular design with a dynamic voltage boosting feature over a wide range of input voltages. The basic configuration of the proposed topology is able to generate three output voltage levels. It is comprised of an integrated SB module and a Quasi-H-Bridge (QHB) cell. The QHB cell consists of a self-balanced floating capacitor and four power switches, and the SB cell consists of a boost inductor and a single power switch. A five-level boosted output voltage can be achieved through the differential connection of two identical QHB cells utilizing a single SB module. The circuit description of the proposed topology, a comparative study, and the simulation and measurement results are given to verify the feasibility of this proposal.

Multilevel inverters (MLIs) based on the flying capacitor (FC) concept are beneficial in many renewable energy-based applications due to their compactness, low current stress on semiconductor devices, and reasonable thermal behavior for high-power applications. However, the recently developed FC-based topologies suffer from half dc-link voltage utilization and a variable high-frequency common-mode voltage (HF-CMV). The aim of this paper is to propose an FC-based family of MLIs with a five-level (5L) output voltage, full dc-link voltage utilization, and low HF-CMV. Using redundant states and the phase-shifted sinusoidal PWM technique, the value of the flying capacitor has been reduced significantly. The performance of the converter has been verified using Gallium Nitride (GaN) power switches. Circuit description and a brief comparative study with existing MLIs are given to justify the suitability of the topology.

Common-Ground (CG)-type multilevel inverters exhibit some interesting features in removing the concern of ground leakage current and improving the overall efficiency of the system within a single power processing stage. In this paper, a new reduced-switch count five-level (5L)-CG-based inverter is proposed, which offers a step-up voltage boosting property and can be extended to the three-phase systems whilst maintaining its CG-feature. The circuit descriptions, comparative study and the relevant measurement results for both the single and three-phase systems are presented to verify the feasibility of the proposed topology.

Transformerless (TL) grid-connected photovoltaic (PV) inverters with a common-ground (CG) circuit architecture exhibit some excellent features in removing the leakage current concern and improving the overall efficiency. However, the ability to cope with a wide range of input voltage changes while maintaining the output voltage in a single power conversion stage is a key technological challenge. Considering this, the article at hand proposes a novel dual-mode switched-capacitor five-level (DMSC5L)-TL inverter with a CG feature connected to the grid. The proposed topology is comprised of a single dc source and power diode, three capacitors, four unidirectional, and three bidirectional power switches. Based on the series-parallel switching conversion of the involved switches, the proposed DMSC5L-TL inverter can generate five distinctive output voltage levels during both the boost and buck operation modes with a self-voltage balancing operation for the involved capacitors. A simple dead-beat continuous current controller (DB3C) modulation technique is also used to handle both the active and reactive power exchange while ensuring a fixed switching frequency operation. The proposed circuit description with its DB3C details, the design guidelines with a comparative study, and some experimental results are also given to show the feasibility of the proposed solution for the practical applications.

© 2019 IEEE. This paper presents a novel dual mode six- switch five-level boost-ANPC inverter (5L-DM-ABNPC) topology with wide input voltage range (400 V - 800 V). It consists of one flying-capacitor and six semiconductor switches forming a similar structure to that of conventional 5L-ANPC or 5L-ABNPC inverter. Depending on the magnitude of the input voltage, the converter can operate in buck or boost mode to produce the same ac voltage out. Further, the number and the size of the active and passive components are also reduced with simple PWM control. Consequently, this make the overall system appealing for various industrial applications. The analysis shows that the proposed topology is suitable for wide range of power conversion applications (for example, rolling mills, fans, pumps, marine appliances, mining, tractions, and most prominently grid-connected renewable energy systems). Simulation and experimental prove the concept of the proposed inverter. The principle of operation and theoretical analysis supported by key simulation and preliminary experimental waveforms are presented.