Search Results (10)

This paper introduces a non-isolated ultra-high voltage gain topology using the combination of the coupled-inductor-based inverting buck-boost converter (IBB) and voltage multiplier (VM) structure. In the proposed converter, an ultra-high step-up voltage gain can be achieved with a small duty cycle thanks to a coupled inductor and VMs. The voltage stress and the losses of the switches in the proposed converter are even less than other conventional topologies. Unlike other coupled-inductor topologies, a large voltage spike caused by the leakage inductance of the coupled inductor is smoothed by the capacitor in the voltage multiplier. In addition, zero-voltage switching (ZVS) turn-on for the switches and zero-current switching (ZCS) turn-off for the diodes can be achieved with the energy stored in the leakage inductance. A 360 W (40 V/380 V) prototype converter is implemented to prove the advantages of the proposed converter, with a maximum efficiency of 98.4%. Full article

This article introduces a high-efficiency, high-voltage-ratio bidirectional DC–DC converter based on the Dual-Active-Bridge (DAB) topology, specifically designed for applications involving low-voltage, high-capacity cells. Addressing the critical challenge of enhancing bidirectional power transfer efficiency under ultra-high step-up ratios, which is essential for integrating renewable energy sources and battery storage systems into modern power grids, an optimized control strategy is proposed. This strategy focuses on refining switching patterns and minimizing conduction losses to improve overall system efficiency. Theoretical analysis revealed significant enhancements in efficiency across various operating conditions. Simulation results further confirmed that the converter achieved exceptional performance in terms of efficiency at extremely high voltage conversion ratios, showcasing full-range Zero-Voltage Switching (ZVS) capabilities and reduced circulating reactive power. Specifically, the proposed method reduced circulating reactive power by up to 22.4% compared to conventional fixed-frequency control strategies, while achieving over 35% overload capability. These advancements reinforce the role of DAB as a key topology for next-generation high-performance power conversion systems, facilitating more efficient integration of renewable energy and energy storage solutions, and thereby contributing to the stability and sustainability of contemporary energy systems. Full article

We present a high-power conversion efficiency (PCE) on-chip switched-capacitor (SC) DC–DC step-up converter for a fully implantable neural interface operating with less than a few tens µW from energy harvesting. To improve the PCE in such light loads and wide variations of voltage-conversion ratio (VCR), which is a typical scenario for ultra-low-power fully implantable systems depending on energy harvesting, a phase-reduced soft-charging technique has been implemented in a step-up converter, thereby achieving very low VCR-sensitive PCE variation compared with other state-of-the-art works. The proposed DC–DC converter has been fabricated in a standard 180 nm CMOS 1P6M process. It exhibits high PCE (~80%) for wide input and output ranges from 0.5 V to 1.2 V and from 1.2 V to 1.8 V, respectively, with switching frequencies of 0.3–2 MHz, achieving a peak efficiency of 82.6% at 54 µW loads. Full article

An ultra-high step-up, non-isolated DC–DC converter with a continuous input current was developed as a result of this research. This converter’s architecture consists of a voltage multiplier cell (VMC), a positive output super lift Luo converter (POSLLC), and a quadratic boost converter (QBS) (also referred to as a cascaded boost topology (CBT)). Thus, the bold points of the topologies mentioned earlier enhance the voltage gain of the proposed topology. It is important to note that when the duty cycle is at 50%, the converter attains a voltage gain of ten. Additionally, the constant input current of the topology reduces the current stress on the input filter capacitor. This converter’s topology was investigated and studied under various operating conditions: ideal and non-ideal modes, as well as continuous and discontinuous current modes (CCM/DCM). The converter’s efficiency and voltage gain were also compared to those of newly proposed converters. PLECS and MATLAB software tools were used in the investigation of the proposed topology. A 200 V/200 W prototype was constructed. The experimental results validated the theoretical study and the simulation results. The extracted efficiency was 91%. Full article

Many photovoltaic (PV) parks suffer from a decrement in their generated power capability due to a phenomenon called potential induced degradation (PID). In this paper, a regenerative system using a high step-up DC–DC converter is proposed, for regenerating PV cells that have been degraded due to the PID effect. The same device also can be used for artificially creating PID on PV panels in order to study the effects of the PID under controlled conditions. The power converter offers multiple voltage levels at the output to adapt to various voltage ratings of PV parks. The device has plug-and-play features, ultra-low cost, small size and is simple in operation. Experimental tests are conducted in real PV panels and comparative results verify the operational principles of the proposed system. The artificial creation of the PID phenomenon and the regeneration of the PV cells are successfully proven experimentally. Full article

A dual-input high step-up isolated converter (DHSIC) is proposed in this paper, which incorporates Sheppard Taylor circuit into power stage design so as to step up voltage gain. In addition, the main circuit adopts boosting capacitors and switched capacitors, based on which the converter voltage gain can further be improved significantly. Since the proposed converter possesses an inherently ultra-high step-up feature, it is capable of processing low input voltages. The DHSIC also has the important features of leakage energy recycling, switch voltage clamping, and continuous input-current obtaining. These characteristics advantage converter efficiency and benefit the DHSIC for high power applications. The structure of the proposed converter is concise. That is, it can lower cost and simplifies control approach. The operation principle and theoretical derivation of the proposed converter are discussed thoroughly in this paper. Simulations and hardware implementation are carried out to verify the correctness of theoretical analysis and to validate feasibility of the converter as well. Full article

Microbial Fuel Cell (MFC) technology is a novel Energy Harvesting (EH) source that can transform organic substrates in wastewater into electricity through a bioelectrochemical process. However, its limited output power available per liter is in the range of a few milliwatts, which results very limited to be used by an Internet of Things (IoT) smart node that could require power in the order of hundreds of milliwatts when in full operation. One way to reach a usable power output is to connect several MFCs in series or parallel; nevertheless, the high output characteristic resistance of MFCs and differences in output voltage from multiple MFCs, dramatically worsens its power efficiency for both series and parallel arrangements. In this paper, a Power Management System (PMS) is proposed to allow maximum power harvesting from multiple MFCs while providing a regulated output voltage. To enable a more efficient and reliable power-harvesting process from multiple MFCs that considers the biochemical limitations of the bacteria to extend its lifetime, a power ranking and MFC health-protection algorithm using an interleaved EH operation was implemented in a PIC24F16KA102 microcontroller. A power extraction sub-block of the system includes an ultra-low-power BQ25505 step-up DC-DC converter, which integrates Maximum Power Point Tracking (MPPT) capabilities. The maximum efficiency measured of the PMS was ~50.7%. The energy harvesting technique presented in this work was tested to power an internet-enabled temperature-sensing smart node. Full article

A new step-up converter with an ultrahigh voltage conversion ratio is proposed in this paper. Two power switches of such a converter, which conduct synchronically, and its output voltage, which has common ground and common polarity with its input voltage, lead to the simple control circuit. No abrupt changes in the capacitor voltage and the inductor current of the proposed step-up converter mean that it does not suffer from infinite capacitor current and inductor voltage. Two input inductors with different values can still allow the proposed step-up converter to work appropriately. An averaged model of the proposed step-up converter was built and one could see that it was still fourth-order even with its five storage elements. Some theoretical derivations, theoretical analysis, Saber simulations, and circuit experiments are provided to validate the effectiveness of the proposed step-up converter. Full article

In high voltage direct current (HVDC) power transmission of offshore wind power systems, DC/DC converters are applied to transfer power from wind generators to HVDC terminals, and they play a crucial role in providing a high voltage gain, high efficiency, and high fault tolerance. This paper introduces an innovative multi-port DC/DC converter with multiple modules connected in a scalable matrix configuration, presenting an ultra-high voltage step-up ratio and low voltage/current rating of components simultaneously. Additionally, thanks to the adoption of active clamping current-fed push–pull (CFPP) converters as sub-modules (SMs), soft-switching is obtained for all power switches, and the currents of series-connected CFPP converters are auto-balanced, which significantly reduce switching losses and control complexity. Furthermore, owing to the expandable matrix structure, the output voltage and power of a modular converter can be controlled by those of a single SM, or by adjusting the column and row numbers of the matrix. High control flexibility improves fault tolerance. Moreover, due to the flexible control, the proposed converter can transfer power directly from multiple ports to HVDC terminals without bus cable. In this paper, the design of the proposed converter is introduced, and its functions are illustrated by simulation results. Full article

In this paper, a novel step-up converter is proposed, which has the particular features of single semiconductor switch, ultra-high conversion ratio, galvanic isolation, and easy control. Therefore, the proposed converter is suitable for the applications of fuel-cell power system. Coupled inductors and switched capacitors are incorporated in the converter to obtain an ultra-high voltage ratio that is much higher than that of a conventional high step-up converter. Even if the turns ratio of coupled inductor and duty ratio are only to be 1 and 0.5, respectively, the converter can readily achieve a voltage gain of up to 18. Owing to this outstanding performance, it can also be applied to any other low voltage source for voltage boosting. In the power stage, only one active switch is used to handle the converter operation. In addition, the leakage energy of the two couple inductors can be totally recycled without any snubber, which simplifies the control mechanism and improves the conversion efficiency. Magnetic material dominates the conversion performance of the converter. Different types of iron cores are discussed for the possibility to serve as a coupled inductor. A 200 W prototype with 400 V output voltage is built to validate the proposed converter. In measurement, it indicates that the highest efficiency can be up to 94%. Full article