Mid Sweden University

In this paper, a switched-capacitor multilevel inverter with voltage boosting and common-mode-voltage reduction capabilities is put forth. The proposed inverter is synthesized with one-half bridge and several switched-capacitor cells. Due to the voltage boosting and common-mode current reduction features, the proposed multilevel inverter is suitable for grid-connected PV applications. In addition, an analytical lifetime evaluation based on mission profile of the proposed inverter has been presented to derive lifetime distribution of semiconductors. Whereas in the proposed inverter, any components failure can bring the whole system to a shutdown. The series reliability model is used to estimate the lifetime of the overall system. The performance of the suggested multilevel inverter in grid-connected applications is verified through the simulation results using the grid-tied model in Matlab/Simulink. Moreover, the viability and feasibility of the presented inverter are proven by using a one kW lab-scaled prototype.

This paper presents a new multilevel converter with a reduced number of power components for medium voltage applications. Both symmetric and asymmetric structures of the presented multilevel converter are proposed. The symmetric topology requires equal dc source values, whereas the asymmetric topology uses minimum switch count. However, both structures suffer from high blocking voltage across the switches. To reduce the blocking voltage on switches, an optimal topology is presented and analyzed for the selection of the minimum number of switches and dc sources, while maintaining a low blocking voltage across the switches. A comparative analysis with recently published topologies was performed. The simulation results, as well as the comparative analysis, validated the robustness and effectiveness of the proposed topology in terms of the reduced power loss, lowered number of components, and cost. Furthermore, in addition to the simulation results, the performance of the proposed topology was verified using experimental results of 9, 17, and 25 evels. 

In this paper, a basic unit for the nine‐level converter is firstly presented. Then, a new developed basic unit topology for the multilevel converter is proposed. This topology comprises several bidirectional and unidirectional switches along with dc voltage sources. In order to increase the number of generated levels, a cascade topology based on the series connection of developed basic units is studied. Due to the extensive nature of the presented cascade multilevel converter, the optimization analysis is presented for generating the maximum number of levels with minimum numbers of IGBTs, drivers, dc voltage sources, and voltage on switches. All required mathematical analysis consisting of switching losses, conduction losses, and voltage on switches is illustrated. In order to indicate the merits of the proposed multilevel converter, comparison results are provided. It is shown that the presented topology uses the least numbers of power electronic components. Also, the voltage on the switches in the presented cascade topology is low. For controlling the switches, a modified triangular carrier signal for dual pulse generation is proposed. The performance of the proposed multilevel converter is proven with experimental results of a typical 25‐level converter.

This paper presents a new switched-ladder structure for multilevel converter which consists of several bidirectional and unidirectional switches along with DC voltage sources. The values of DC sources in the proposed topology are determined based on a new mathematical algorithm. The proposed multilevel converter is an extended structure, which can produce any levels at output voltage waveform. To prove the merits of the proposed structure, the proposed converter is compared with other similar structures. According to comparison results, it is shown that the presented structure requires the least numbers of DC sources, IGBTs, drivers and on-state switches. Also, the value of voltage rating of the switches is analyzed. The experimental results are provided for the proposed 17-level converter to prove the performance of suggested structure. 

This paper presents a new seven-level grid-connected converter with capability of voltage boosting. This topology utilizes a switched-capacitor unit along with an H-bridge. The proposed converter is compared with other recent proposed seven-level converters. The comparison results verify that the proposed seven-level converter needs lower switches, dc voltage sources, and diodes compared to other structures. Also, the total voltage on switches in the proposed converter is low. In order to achieve low total harmonic distortion, unity power factor, and current injection to the grid, model predictive controller is used. The feasibility of the proposed converter is proven by experimental works. 

This paper presents a new seven-level grid-connected converter with capability of voltage boosting. This topology utilizes a switched-capacitor unit along with an H-bridge. The proposed converter is compared with other recent proposed seven-level converters. The comparison results verify that the proposed seven-level converter needs lower switches, dc voltage sources, and diodes compared to other structures. Also, the total voltage on switches in the proposed converter is low. In order to achieve low total harmonic distortion, unity power factor, and current injection to the grid, model predictive controller is used. The feasibility of the proposed converter is proven by experimental works.

Compact power converters are the major concern of today’s power industry. This article proposes GaN devices based isolated dc-dc phase shifted full bridge converter along with the configuration of four series-connected hybrid transformers. The series connection of transformers reduces the applied volt-second on each transformer which reduces the proportional losses and simplify thermal management. This configuration also reduces the required turn’s ratio as well as bringing down the stress on the secondary devices and filters. The converter is characterized in a compact prototype up to the load power of 2.2 kW for Vout=48 Vdc at Vin=400 Vdc. The converter reports satisfactory performance with a maximum efficiency of 96%.

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.