A new ultra-high gain CI-based DC/DC converter with low voltage and current stresses.

A new step-up quadratic DC/DC converter based on coupled-inductor

This article introduces a novel ultra-high voltage gain DC-DC converter with a low component count, designed for renewable energy applications. In the presented topology, a three-winding coupled-inductor (TWCI) and a switched-capacitor network are embedded within a classic quadratic boost converter. This arrangement yields high voltage gain, ensures continuous low-ripple input current, and preserves a common ground between the source and the load. Due to its trans-inverse feature, the circuit achieves ultra-high voltage gain even with a very low turns ratio in the TWCI. The topology also features current sharing between the TWCI and the main power switch, which significantly reduces power losses in the main power switch and coupled-inductor device. To limit voltage stresses on the active switches, the circuit integrates two passive regenerative clamp circuits, with the switches themselves operated using simultaneous switching patterns. The paper provides detailed steady-state analysis, power loss calculations, comparative evaluation, and design considerations. Finally, a laboratory prototype rated at 200 W has been implemented to verify the theoretical analysis, achieving a very high voltage conversion from 20 V input to 400 V output.

An ultra high-gain switched-capacitor-inductor DC-DC converter with reduced voltage stress.

This paper introduces a new non-isolated step-up DC-DC converter based on a switched-capacitor-inductor (SCI) network that achieves high voltage gain at modest duty cycles. The proposed topology is distinguished by several simultaneous merits: low voltage stress on all power switches and diodes, a common ground between the input and output ports, continuous input current, and a superior gain-per-component ratio with respect to inductors, capacitors, and diodes. Thanks to the reduced semiconductor voltage stress, switching losses are mitigated, and the converter can employ lower-voltage active devices, which are inherently more efficient and cost-effective. The converter also features an inherently modular multi-stage structure, allowing it to scale to higher voltage and power levels without proportionally increasing semiconductor stress, which is an advantage over conventional quadratic or coupled-inductor-based high-gain designs. The paper presents a comprehensive steady-state analysis in both continuous (CCM) and discontinuous (DCM) conduction modes, derives the voltage gain and component stresses, and provides a detailed comparative evaluation against state-of-the-art step-up topologies in terms of voltage gain, semiconductor stress, component count, and efficiency. A 400 W laboratory prototype with 48 V input and 400 V output, operating at 25 kHz, was built and tested. Experimental results confirm the theoretical analysis and demonstrate a measured efficiency of 94.9%.

A Novel Ultra‐High Gain Quadratic DC–DC Converter Based on Improved Sepic Structure

This article proposes a high‐gain quadratic DC–DC converter derived from the improved Sepic structure. By integrating a voltage multiplier cell, a coupled inductor, and a new quadratic voltage‐boosting stage, the design provides ultra‐high and adaptable voltage conversion ratios, resulting in significantly enhanced gain capability. Despite the substantial increase in voltage gain, the design maintains low voltage stress on the components. Passive clamping circuits are incorporated for both switching transistors, which effectively suppress voltage spikes by recycling the energy stored in the leakage inductance. Furthermore, the inclusion of a single input inductor ensures a continuous input current. Additional advantages of the proposed topology encompass reduced voltage stress across the semiconductor devices and a nonisolated, common‐ground configuration. These features enhance its suitability for renewable energy integration. A comprehensive examination is provided, covering detailed steady‐state analysis, a parameter design guideline, and a loss analysis. The effectiveness of the converter is validated through a 200 W experimental prototype, delivering an output voltage of 400 V. This prototype demonstrates a peak full‐load efficiency of 95.41%, thereby confirming the topology's superior performance in energy conversion systems.

A Group of High Step-Up DC–DC Topologies Based on Conventional Buck-Boost Converter Utilizing Coupled-Inductors and Voltage Multipliers

Traditional high step-up DC–DC converters for renewable energy sources (RESs) often suffer from critical limitations, including the requirement for extreme duty cycles to achieve high voltage gains, elevated voltage and current stresses on semiconductors, and the imposition of full output voltage on the output capacitor and diodes. This paper presents a single-switch, non-isolated high step-up DC–DC converter that overcomes these challenges by combining a coupled inductor (CI) and voltage multiplier (VM) cells with a modified buck–boost–converter-based structure. The proposed topology achieves a high voltage conversion ratio while effectively distributing voltage stresses among the circuit components. The coupled inductor mitigates diode reverse-recovery problems, and a passive clamp circuit suppresses voltage spikes arising from leakage inductance, thereby reducing switch stress and enhancing its efficiency. Comprehensive theoretical analysis, along with comparative evaluations against similar configurations, demonstrates that the proposed converter delivers high voltage gain across the full duty-cycle range with the minimum normalized switch voltage stress. It also exhibits among the lowest diode voltage stresses and utilizes relatively low-value passive components, all within a simple structure employing only one power switch and one magnetic core. Four extended topologies utilizing an extra inductor or coupled inductor alongside an extra power switch, offering one more degree of freedom are also developed, analyzed in their various operational states, and simulated in this paper. Experimental validation of the main topology, operating at 300 W and 50 kHz while stepping up 30 V to 380 V, confirms the provided analyses and proper practical performance.

A high step-up DC–DC converter with voltage multiplier cell for renewable energy systems

This paper proposes a novel high step-up DC–DC converter topology featuring two synchronously controlled power switches driven by identical gate signals, thereby simplifying the control circuit. The proposed converter (PC) employs an input inductor to ensure continuous input current and a three-winding coupled inductor to achieve ultra-high voltage conversion gain. In addition, a voltage-multiplier cell is incorporated to further enhance the output voltage gain (VG). A passive-clamp circuit is utilized to recycle leakage energy, reduce voltage spikes, and improve overall efficiency. The converter is analyzed under both continuous conduction mode (CCM) and discontinuous conduction mode (DCM), including the derivation of VG characteristics and CCM/DCM boundary conditions. A comprehensive theoretical investigation is presented, covering steady-state operation, VG, voltage and current stresses of semiconductor devices, component design considerations, power-loss analysis, small-signal modeling, control design, and dynamic response characteristics. Compared with recently reported high step-up converters, the proposed topology achieves an improved trade-off among VG, switch stress, magnetic complexity, and component count through the coordinated integration of the coupled-inductor structure, voltage-multiplier cell, and passive-clamp circuit. To validate the theoretical analysis, a 200 W laboratory prototype with a 24 V input and 400 V output was designed and implemented in both simulation and hardware. Experimental results demonstrate a peak efficiency of 96.7% at 40% load and 95.7% at full load, confirming high efficiency over a wide operating range. These results verify the effectiveness and suitability of the PC for renewable-energy and high step-up power-conversion applications.

A High-Gain DC-DC Converter with Input Ripple Mitigation and Switch Stress Suppression