Wireless power transfer (WPT) has attracted a lot of attention these years due to its convenience, safety, reliability, and weather proof features. First and foremost, the consistency of mutual model and T model of loosely coupled transformer (LCT) was deduced. The application scenarios of these two models were then concluded so as to choose suitable model in circuit analysis. Then, a new WPT compensation topology, which is referred to as LC /S compensation topology and consists of one inductor and two capacitors, is proposed. The constant-current-output (CCOut) characteristic of the newly proposed topology is analyzed in detail on the basis of the discussion about LC and CL resonant tank. The equivalent resistance of the rectifier, filter, and resistor circuit is also analyzed to simplify circuit analysis. Then, the current and voltage stress on each component and the system performance under imperfect resonant condition are studied with the help of MATLAB. The LCT is deliberately designed by the finite element analysis software ANSYS Maxwell as well because the coupling coefficient, primary, and secondary self-inductance have a significant impact on system efficiency, power level, and density. The LCT design approach employed in this paper can be extended to magnetic design of almost all WPT systems. Theoretical analyses are verified by both Pspice simulation and practical experiments. Practical output currents with transient loads show an excellent CCOut characteristic of LC/S compensation topology.

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.

In this paper, the fixed-time control problem of DC-DC buck converter systems with mismatched disturbances is investigated. Firstly, the sliding mode fixed-time observers are constructed to estimate the matched and mismatched disturbances of the systems. Secondly, a novel segmented terminal sliding mode control (TSMC) variable considering the mismatched disturbance of the system is designed based on the observations. To improve the tracking performance, a new second-order fixed-time reaching law is proposed. Then, in order to make the DC-DC buck converter systems with mismatched disturbances achieve accurate control in a fixed-time independent of the initial state, a novel fixed-time nonsingular TSMC based on the fixed-time observers is proposed. Finally, comparative experiments are conducted to verify the effectiveness and practicality of the proposed control strategy.

Wireless power transfer (WPT) has attracted a large amount of attention owing to its inherent advantages such as convenience, safety, low maintenance, weather proof, etc. Parameter tuning method is crucial for WPT system due to its function of reducing reactive power and improving system efficiency. Three deficiencies of conventional double-sided LCL (DS-LCL) compensated system, low design freedom, weak high-order harmonic suppression capability and discontinuous input current of full-wave diode rectifier (FDR), are firstly analyzed by means of theoretical derivation, numerical calculation and Pspice simulation. In order to overcome these disadvantages, a novel parameter tuning method is proposed. The characteristic of constant current output of the proposed DS-LCL system is analyzed, followed by detailed derivation about secondary compensation inductance. Theoretical analysis indicates the proposed system has four attractive characteristics including higher design freedom, reduced coil current, enhanced high-order harmonic suppression capability and continuous input current of FDR. The overall efficiencies of two comparative WPT prototypes, tuned by conventional and proposed methods, are 87.3% and 90.2% respectively. Experimental results show great coincidence with theoretical analysis, demonstrating the superiority of newly proposed parameter tuning method.

Wireless power transfer (WPT) has drawn a lot of attention due to its inherent advantages and great potential in various applications. This paper proposes a novel compensation topology composed of one compensation inductor and three compensation capacitors. The newly proposed compensation topology, named as S/CLC, provides the advantages of constant voltage output and easy achievement of zero phase angle and zero voltage switching. It is also free from the constraints imposed by the loosely coupled transformer (LCT) parameters. All the above-mentioned merits are theoretically analyzed and verified by simulation and experiment. Compared to doublesided LCC compensation topology, S/CLC compensation topology needs less compensation components, meaning lower cost, smaller size, higher power density, and greater potential in practical applications. The optimization of a circular pad is conducted as well since the properties of the LCT have a significant impact on the performance of a WPT system. A circular pad is manufactured in terms of the conclusions obtained from the optimization. The coupling coefficient Circular pad design, constant voltage output (CVO), wireless power transfer (WPT), zero phase angle (ZPA), zero voltage switching (ZVS).of the circular pad is quite appealing, demonstrating the validity of the 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.