Non-isolated high step-up DC/DC power converter with coupled-inductor

This paper presents a non-isolated single switch converter with high voltage gain. Its circuit topology is combined with coupled-inductor, clamp circuit, and voltage lift capacitor techniques. The proposed converter has several advantages: First, the circuit is controlled by only single pulse width modulation (PWM) for the power switch, which keeps the circuit simple. Secondly, the proposed converter is used as a clamping circuit,which let the energy of the leakage inductance can be circulated to the capacitor, so that the voltage spike on the active switch can be suppressed, and improves efficiency. This paper will introduce the principle of action, theoretical analysis, and experimental waveform in order. Finally, in the case of input voltage of 48 V, output voltage of 400 V, and output power of 1 kW, the performance of the proposed converter is verified. As a result, the maximum efficiency is up to 96.5% and full load efficiency is 92.3%.

A Case Study: Influence of Circuit Impedance on the Performance of Class-E2 Resonant Power Converter for Capacitive Wireless Power Transfer

The evolution of power electronics led to rapid development in wireless charging technology; as a result, a single active switch topology was introduced. The present market utilizes inductive wireless power transfer (IPT); because of the disadvantages of cost, size, and safety concerns, research on wireless power transfer was diverted towards capacitive wireless power transfer (CPT). This paper studies the optimal impedance tracking of the capacitive wireless power transfer system for maximum power transfer. Compared to prior methods developed for maximum power point tracking in power control, this paper proposes a new approach by means of finding impedance characteristics of the CPT system for a certain range of frequencies. Considering the drone battery as an application, a single active switch Class-E2 resonant converter with circular coupling plates is utilized. Impedance characteristics are identified with the help of equations related to the input and resonant impedance. The impedance tracking is laid out for various resonant inductors, and the difference in current peak is observed for each case. Simulations verify and provide additional information on the reactive type. Additionally, hardware tests provide the variation of input current and output voltage for a range of frequencies from 70 kHz to 300 kHz. Efficiency at the optimal impedance points for a resonant inductor with 50 μH and 100 μH are tested and analyzed. It is noted that the efficiency for a resonant inductor with 50 μH is 8% higher compared to the CPT with a 100 μH resonant inductor. Further hardware tests were performed to investigate the impact of frequency and duty cycle variation. Zero-voltage-switching (ZVS) limits have been discussed with respect to both frequency and duty cycle.

A Transformer less Buck-Boost Converter with Single Switch

This paper introduces a modern, transformerless buck-boost dc-dc converter. In this topology, one active switch is used. The proposed buck-boost converter voltage gain is higher compared to the conventional buck-boost converter. With a moderate duty cycle, high voltage gain can be reached. The switch's voltage stress is minimal. As a consequence, the power switch's conduction loss is relatively low to improve efficiency. The converter is simple, hence it will be easy to control the proposed converter.