In this paper, a high step up converter consisting of an integrated dual-boost converter and a voltage doubler is proposed. The integration of the dual-boost converter makes the system easier to lift up its voltage gain through slightly increasing the duty ratio of the single switch. The voltage doubler further increases the voltage gain of the system as the turn ratio rises. The voltage stresses on the switch and the diodes are decreased for such cascaded topology. Different operation modes are analyzed and mathematical analysis of the converter is presented in detail. The leakage inductances contribute to realizing zero current switching (ZCS) of the diodes in the second boost stage and the doubler and the energy can be recycled to the load. A 38W prototype is built to work as a vehicle LED driver. Experiments are conducted to verify the advantages of the proposed converter and the efficiency is 90% at the nominal operating point.

The development of high-frequency power converters is continuously improving their power density, efficiency and fast dynamic response. Among them, high-voltage-conversion-ratio (HVCR) dc–dc converters are widely used in high gain, i.e., step-up/-down or bidirectional applications, such as power supply for data center, dc micro-grids, electrical vehicle charging systems, etc. In this article, the current main high-frequency HVCR dc–dc converters are classified into inductive-based and capacitive-based approaches, which can then be described further by four kinds in detail, namely transformer-based, coupled-inductor-based, and switched-capacitor-based, as well as combination of coupled inductor and switched capacitor. A comprehensive analysis and comparison is given, which can provide guidance for proper topology selection and further topology optimization.

Development of power electronic converters tend to achieve high efficiency and at the same time high power density in many industrial applications. In recent years, with emerging third-generation semiconductor materials i.e. Silicon Carbide (SiC) and Gallium Nitride (GaN), the switching frequency of several MHz has become a widely studied frequency band, therefore traditional technology can no longer meet the demand, and many new challenges appear. This paper presents a comprehensive review of high frequency (HF) converters, the essential challenges are analyzed such as topology selection, soft-switching technologies, resonant gate drivers, magnetic components design and optimization.

As a power supply method with high spatial freedom, megahertz (MHz) wireless power transfer (WPT) has great potential in particular application fields. The role and importance of WPT are described from the perspective of interdisciplinary. This article starts with WPT systems’ performance at different frequencies, emphasizes the basic composition and working principle of MHz systems, and focuses on a comprehensive review of recent years on inverters, rectification, impedance compression, dynamic impedance matching, coupling structure design, and multiload model establishment. Meanwhile, different technologies are summarized, compared, and classified. Current challenges and future development trends are discussed.

A novel high step-up DC-DC converter with coupled inductor and switched capacitor is proposed in this paper. The proposed converter adopts capacitors charged in parallel and discharged in series with a couple d inductor to achieve high step-up voltage gain. By utilizing the energy stored in the leakage of the coupled inductor, both of the switches can realize zero-voltage switching, which can reduce switching loss and improve efficiency. In addition, the voltage stress of the switches and diodes are also reduced. Therefore, low voltage components can be utilized. And the input current is continuous. The operating principle, steady-state and parameter design are depicted in detail, and a 100W experimental prototype with 25V input voltage and 380V output voltage is established in the laboratory to verify feasibility of the proposed converter, and the highest efficiency is 96.21%.

In this paper, a novel modified SEPIC converter based on transformer is proposed. With the integration of some passive components, the proposed converter obtains better performance such as high voltage gain, low voltage stress and soft switching characteristic which is suit for high frequency and high voltage gain applications like photovoltaic and fuel cell systems. For better high frequency characteristics, GaN switch and planar magnetic components based on high frequency material are used. Moreover, in the process of magnetic component optimization, an integrated scheme is applied to improve power density, and partly interleaved structure is adopted for lower parasitic capacitance as well as leakage inductance. Working principles, accurate steady state analysis and optimization process are presented in detail. An 80W prototype has been designed to demonstrate theoretical analysis. Obtained efficiency was up to 93.1% at full load. Experimental results show good agreement with theoretical analysis and high feasibility of proposed converters.