No abstract

Summary In this paper, a novel non‐isolated very high step‐up DC‐DC converter is presented. The introduced converter benefits from various advantages, namely, very high voltage gain, low voltage stress on the active switch, and continuous input current with low ripple. Therefore, the presented converter is suitable for renewable energy applications. In addition, the energy of the leakage inductance of the coupled inductor is successfully recovered, and the voltage spike of the active switch is clamped during the turn‐off process. Hence, a switch with low Rds−on can be used, which decreases the conduction losses as well as cost of the converter. Furthermore, the voltage stress of the output diode is decreased, which reduces the reverse recovery problem. The steady‐state analysis and design considerations of the proposed converter are discussed. Finally, the theoretical analysis is validated with the experimental results at an output power of 150 W.

In this paper, a novel zero current switching (ZCS) flyback inverter in discontinuous conduction mode (DCM) is proposed. In the proposed flyback inverter, the ZCS for the primary switch is achieved by adding a simple auxiliary circuit to the conventional flyback inverter. Also, the auxiliary switch is turned on and turned off at ZCS condition. Therefore, the switching losses of the switches are negligible, which increases the efficiency and allows higher switching frequency and more compact design. The resonant auxiliary cell is activated only in short transition times that makes its conduction losses negligible. Furthermore, the voltage overshoot of the main switch is limited during the turn-off process, which allows utilization of lower voltage metal-oxide semiconductor field-effect transistors (MOSFETs) with low conduction losses and low cost. The detailed operation of the flyback inverter with auxiliary circuit and design considerations are presented. Simulation and experimental results are presented to verify the performance of the proposed inverter.

This is a repository copy of Analysis, design and modelling of two fully-integrated transformers with segmental magnetic shunt for LLC resonant converters.

This paper presents two topologies which provide high leakage inductance in shunt-inserted integrated magnetic transformers. These differ from conventional designs by replacing the low-permeability magnetic shunt of a planar transformer with highpermeability magnetic shunt segments, separated by many small air gaps. This approach results in a shunt with the same bulk permeability as the conventional design, while using lower cost and readily available magnetic materials such as ferrite. A modelling and design approach which can estimate the leakage and magnetising inductances precisely is provided for each topology. Theoretical analysis is presented and verified using finite-element analysis and experimental implementation. AC resistance analysis for both transformer topologies is also presented. In addition, an LLC resonant converter is built to verify the performance of the proposed fully-integrated magnetic transformers in practice. It is shown that the proposed topologies can integrate all three magnetic components of an isolated LLC resonant converter in a single planar transformer, which reduces the converter's volume and cost.