In this article, a novel dc–dc light-emitting diode driver employing an interleaved converter is proposed and analyzed. The circuit topology mainly consists of two parallel buck–boost converters. A coupled inductor, which is composed of a magnetic core and two windings, is used to replace the energy storage inductors of the two buck–boost converters. This not only does not add any components, but also saves a magnetic core. The buck–boost converters are designed to operate near boundary conduction mode. Due to the characteristics of magnetic flux balance, the magnetic-excited current can be converted between the windings of the coupled inductor. By using the magnetic-excited current to release the charge stored in the parasitic capacitors of the active switches, these switches can fulfill zero-voltage switching on (ZVS) without the use of any auxiliary switches, active clamping circuits, or snubber circuits. Moreover, the freewheel diodes of both buck–boost converters can achieve zero-current switching off (ZCS). The steady-state analyses for different operation modes are provided, and the mathematical equations for designing circuit components are conducted. Finally, a 200-W prototype circuit was built and tested to verify the analytical predictions. According to the experimental results, all the semiconductor devices are operated at either ZVS or ZCS, and the circuit efficiency as high as 95.0% is measured. Satisfactory performance has verified the feasibility of the proposed converter.

The prospect of using robots in warehouses or supply chain processes is increasing due to the growth of the online retail market. This logistic robot is available in the market and uses a battery as energy storage device. However, this battery is large and heavy. Therefore, it needs a long recharging time. Dynamic Wireless Power Transfer (DWPT) can be an alternative to the conventional charging system because of its safety and flexibility that enables in motion charging. DWPT reduces the battery requirement size and capacity. Hence the stored energy can be used effectively for load transportation. A compensation with an inductor and two capacitors in the transmitter side, and a series connected capacitor in the receiver side which is named LCC-S compensation type has the capability to maintain the transmitter current with a fixed frequency operation. It provides less variation of the output voltage in response to the load variation. Moreover, the compensation of the receiver side uses only a single series capacitor which is low-cost. The analysis, modeling, and design procedures are discussed in this paper as well as the hardware implementation and verification of a 1.5 kW maximum power DWPT. The experiment shows the capability of the proposed system and shows maximum efficiency can reach 91.02%.

In this study, a novel modulation of an isolated three-phase bidirectional dc-dc converter is proposed for the high-voltage input power supply to low-voltage output energy storage systems. The wye-delta connection of the transformers is employed to reduce the voltage stress at the high side and the current stress at the low side of the transformers. Frequency control allows the output voltage regulation, and a phase-shift algorithm with a resonant tank is proposed following with the switching frequency to reduce the frequency range with the specific power. Furthermore, the zero-voltage-switching condition for all mosfets in the entire power range, which is the major restriction of a single-phase converter, is also discussed in this paper. The three-phase wye-delta converter significantly reduces the ripple of inductor current compared with that of a single-phase converter. A 2 kW prototype converter was built and successfully tested to verify the capability of such control modulation.