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 conventional phase-shifted full-bridge (PSFB) converter is one of the most promising topologies in high efficiency and high power applications because of its small RMS current, inherent zero-voltage switching (ZVS) capability, and clamped voltage stress of the primary switches. However, when the PSFB converter operates with a small duty-ratio, a large freewheeling current of an output inductor flows in the primary side, and it causes a large circulating current. In addition, it has a large voltage stress in the rectifier diodes due to a voltage ringing between parasitic components. To solve these problems, a new PSFB converter with a coupled inductor rectifier (CIR) is proposed in this paper. By adopting the CIR structure in the PSFB converter instead of the full-bridge rectifier, the proposed converter eliminates the freewheeling current in the primary side which significantly reduces the primary circulating current. In addition, the two rectifier diodes of the CIR do not have voltage ringing. As a result, the proposed converter not only reduces the conduction loss in the primary side, it can also use two diodes in the rectifier with a low voltage rating. The effectiveness and feasibility were verified with a 320-400 V input and 56 V/12.8 A output prototype.

As satellite missions become increasingly diverse, the power capacity of satellites continues to increase. Accordingly, the weight and loss of the electrical power system of the satellite must be reduced. Thus, a high bus voltage is required for the electrical power system of the satellite. However, most high-power dc/dc converter topologies, such as half-bridge and full-bridge dc/dc converters have leg-structures, which violate the heritage design characteristics of the dc/dc converters for satellites. To solve these problems, a two-switch forward converter with an integrated buck converter is proposed in this article. By integrating the buck converter into the two-switch forward converter, one switch and one diode are eliminated in the proposed converter, and consequently, its cost, weight, and volume can be greatly reduced. Moreover, the zero-voltage switching of the low-side switch can be achieved. Therefore, the proposed converter achieves a high efficiency under the entire load condition compared with conventional converters. The effectiveness and feasibility of the proposed converter were verified with a prototype of 300–330 V input and 600 W (150 V/100 V) output.

In photovoltaic applications, many previous researches have focused on pulse width modulation (PWM) resonant converters in order to achieve a high efficiency with a wide input voltage range. Conventional approaches utilized symmetric boosting modulation at the secondary side rectifier to obtain a symmetric operation, and they utilized two boosting modes in a switching period. Among various rectifier structures, the voltage doubler structure has a strong advantage due to a small number of components. However, it suffers from serious hard switching losses in the secondary side rectifier. In this paper, a new converter with a novel asymmetrical modulation is proposed and verified. The strong point of the proposed converter is that it eliminates hard switching turn on losses from the rectifier, while maintaining the minimized number of components. Although the proposed converter adopts an asymmetric modulation, the offset current on the transformer becomes zero inherently. Furthermore, a “forced half resonance” operation of the proposed converter keeps RMS current stresses at the same level as conventional converter although it has a higher peak current. Accordingly, the proposed converter achieves a superior efficiency with the minimum number of components at 35–25V input and 380V/300W output specification.

With rapid developments in the satellite data services market, the demand for low Earth orbit (LEO) satellites is increasing. Advancements in designing lightweight satellites are essential to maximize profits from the mass production of LEO satellites in private companies. This paper proposes a new direct charging control suitable for electrical power systems for lightweight and highly reliable LEO satellites. Moreover, an analysis of the proposed solar array regulator (SAR) in terms of weight, efficiency, and reliability is presented. Additionally, the advantages of the proposed SAR in terms of lifespan and state of health (SOH) of Li-ion batteries are presented because the peak value of the battery charging current and the temperature changes during the battery charging operation are relatively small.

This paper proposes high efficiency three-level dc-dc converter with reduced circulating current and rectifier voltage stress by using coupled inductor in the rectifier circuit. Because of decreased circulating current, the conduction loss in the primary circuit is reduced. In addition, since the rectifier diodes with low forward voltage drop can be employed due to the small voltage stress, the conduction loss of rectifier diodes can be reduced. Therefore, the efficiency can be increased due to the reduction of the conduction losses in the primary circuit and rectifier diodes. The characteristics of the proposed converter are analyzed and compared with other three-level converters. The validity of the proposed converter is verified by the experimental results of the prototype with 540-600 VDC input and 750W (48 V/15.625 A) output.