The polar energy router is a key device in the polar clean energy system which converges the output of wind power, photovoltaic units, energy storage units and hydrogen fuel cells through the power electronic power converter to the DC bus, which requires the use of a variety of specifications of DC/DC converters; as a result, the efficiency of the DC/DC converter is directly connected to the efficiency of the polar energy router. This paper presents an enhanced isolated DC/DC converter with a phase-shifted full-bridge topology designed to meet the high-efficiency conversion requirements of polar energy routers. Although soft switching can be realized naturally in phase-shifted full-bridge topology, it also faces challenges, such as the difficulty of realizing soft switching under light load conditions, large circulation losses, a loss of duty cycle and oscillation in the secondary-side voltage. To solve these problems, an improved scheme of the phase-shifted full-bridge converter with an active clamp circuit is proposed in this paper. The scheme realized zero-voltage switch (ZVS) under light load by utilizing clamp capacitor energy. The on-state loss was reduced by zeroing the primary-side current during the circulating phase. This paper provides a detailed description of the topology, working principle and performance characteristics of the improved scheme, and its feasibility has been verified through experiments.

Due to the restrictions of the operating environment and on-site space conditions, the energy routing devices used in Antarctic research stations must have a compact structure and require the internal power converter to have a high enough power density to reduce its size, so the internal DC/DC conversion link of the energy router adopts a two-stage voltage regulation scheme. In this paper, a Switched Tank Converter (STC) is used to realize the coarse voltage adjustment of the first stage. In order to further improve the power density of the STC, this paper integrates the half bridge with the same switching action in the STC, and several resonant slots share one inductor to obtain an H-bridge STC with reduced inductance. At the same time, an improved control method is proposed to solve the influence of passive device parameter error and the parasitic parameter on the resonant frequency by adjusting the on-time value of the switch on the rectifier side. This control method can effectively solve the influence of the passive device parameter difference on the converter without adding new devices, ensure the power density advantage of the converter, and improve efficiency. Finally, the validity and rationality of the circuit and the improved control method are verified by simulation and experiment. The experimental result shows that the H-bridge STC with reduced inductance has a power density of 1041 W/in³ at 600 W, which greatly improves the overall operating efficiency of the energy router.

Poly(vinylidene fluoride) (PVDF) exhibits excellent piezoelectric properties governed by the content and orientation of its polar phases. Herein, a synergistic regulation strategy integrating a flow field induced by a designed solid-phase extrusion die and ion–dipole interactions introduced by CTAB is established to achieve highly oriented β phase in PVDF. The incorporation of CTAB promotes the formation of the γ phase before extrusion, providing a structurally favorable precursor for the subsequent flow-induced γ-β phase transformation. During solid-phase extrusion, the converging flow field drives extensive molecular chain alignment, promoting the γ-β phase transformation and substantially enhancing both β phase content and orientation. The synergistic effects of CTAB-induced ion–dipole interactions and the converging flow field further regulate the melting behavior and crystal perfection of PVDF, driving the transformation of the lamellar structure into highly oriented lamellar bundles along the extrusion direction. Among all compositions studied, the blends containing 5 wt% CTAB exhibit the optimal polar phase content and orientation characteristics, along with the highest dielectric constant. This work elucidates the synergistic regulation of PVDF hierarchical structures by ion–dipole interactions and flow fields, offering an effective strategy for fabricating high-performance piezoelectric PVDF materials.