This letter presents a new single-phase 13-level switched-capacitor inverter with a reduced number of switches and a voltage boost gain of 6. The proposed topology with a single DC source can achieve 13-level output, sextuple boost, and self-voltage balance of capacitors using only 14 switches. The proposed inverter does not use a back-end H-bridge with four switches that must withstand the peak load voltage, and the voltage stress of all switches does not exceed half of the peak load voltage. The operation principle including the self-voltage balance of capacitors is described in detail. An analysis of the proposed inverter in comparison to recent topologies with a single-input DC source is performed mainly in terms of the number of switches and cost function. Simulation and experimental results verify the feasibility of the proposed topology.

A novel resonant dc-dc converter with high-efficiency and low input current ripple is presented. Without adding any components, the proposed converter greatly improves the efficiency of the conventional half-bridge converter that has input current ripple reduction. By using two input capacitors and two leakage inductances of the conventional converter as resonant elements, a new high-efficiency resonant converter with a double LLC resonant tank is achieved. As a result, the proposed converter reduces switching losses by soft switching operation of all primary switches and secondary diodes in a wide input voltage range. Moreover, it can improve the conduction losses by reducing the voltage stress on the secondary diodes. In addition, the output filter inductor is removed, and the ripple and undesired harmonic components caused by the pulsating input current can be significantly reduced without using a large input filter. The operation principle is analyzed, and the experimental results of a prototype verify the feasibility of the proposed converter.

DC distribution systems have garnered interest in recent years due to their advantages over AC distribution systems, such as their high power conversion efficiency and lack of harmonic issues. An isolated DC-DC converter with low-input noise, high efficiency, and high-power density is required for DC microgrids within DC distribution systems. Although existing DC to DC converters have high efficiency and high power density, they still have input noise problems due to pulsating input currents. Thus, a large input filter should be inserted, which increases the cost and degrades the power density. In this study, a novel three-level double LLC resonant converter with zero-input-current ripple is presented for DC microgrid application with a high-voltage DC bus. The input-current ripple of the proposed converter theoretically decreases to zero without adding large input filters. Moreover, the voltage stress on each main switch is only half of the input voltage when using the modified three-level structure, which enables the use of low-voltage-rated power switches for high-voltage input applications. In addition, all the primary switches and secondary diodes are softly switched over a wide input voltage range. The experimental results of the prototype are presented to verify the performance of the proposed converter.

In this paper, a hybrid converter with a new clamp circuit is presented. This hybrid converter has the structure of combining a phase-shifted full-bridge (PSFB)converter with a half-bridge (HB)LLC converter. On the primary side, the lagging-leg of PSFB converter is shared by HB LLC converter. On the secondary side, the full-bridge rectifiers of two converters are connected in series. Due to the series-connected structure on the secondary side, this hybrid converter is suitable for high output voltage applications. In addition, by using a new center-tapped clamp circuit, which consists of two diodes and two capacitors with connected to the center of the transformer, the proposed converter can solve many drawbacks of PSFB converters in wide range of output voltage. Finally, the performance in efficiency, power density, and cost can be improved. In order to validate the feasibility of the proposed converter, a 3.3-kW prototype was tested.

A novel high-efficiency double LLC resonant dc-dc converter with zero input current ripple and low voltage stress is presented. The input current ripple and undesired harmonic components can be significantly reduced without adding a large input filter. Moreover, all main switches and rectifier diodes are softly switched in a wide input voltage range, reducing the switching loss. The voltage stress on each main switch is only half of the input voltage by using the improved three-level structure, which enables the use of low-voltage-rated power switches for high-voltage input applications. The operation principle is analyzed and experimental results of a prototype validate the performance of the proposed converter.