This work focuses on a new non-isolated interleaved DC-DC converter with very high step-down voltage conversion ratio. By employing the switched/series capacitor concept, along with the proper component interconnection, the converter features a high step-down voltage conversion ratio where, in the private case of equal duty ratios, it is six times higher than the conventional buck converter. This high step-down voltage conversion ratio is achieved with the lowest number of components compared to other similar topologies of the same conversion ratio. Also, due to the blocking/series capacitors, the voltage stress on the switches is reduced, improving the converter efficiency. One of the key features of the proposed converter is the inherent automatic current sharing between the interleaved phases, which in the case of equal duty ratios, is uniformly distributed. To add on, due to the use of only two interleaved phases, the converter has a wide output voltage range, since the duty cycle can be extended to 0.5. To validate the proposed converter operation, a 250 W wide-input/wide-output experimental prototype was built, achieving a peak efficiency of 94%. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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.

Several types of energy recovery systems (i.e. shaft generators etc.) have been installed in marine vessels, in order to reduce the fuel consumption and ultimately improve the efficiency of the vessels. In this paper, an energy recovery system utilizing the thermal losses of a real ship is investigated. The main goal of this work is to improve the overall efficiency of the ship. Therefore, a theoretical study and apparatus selection is conducted for every part of a proposed Waste Heat Recovery System. Moreover, simulation results of each part, as well as of the whole system, are presented in this paper.

Mechanical load simulators are useful in various cases, where we wish to test an electromechanical system. A mechanical load simulator can be used to emulate a wide variety of loads, such as industrial loads, electric vehicle drivetrain, etc. In this paper, a load simulator build for the testing of various electromotion systems, with the capability of four quadrant operation (positive or negative torque, positive or negative rotational speed) and very good transient behavior is presented. The four quadrant operation allows bidirectional power flow, thus enables the study of energy recovery braking. The overall system will be investigated, the control method will be analyzed and finally, simulation and experimental results will be presented.

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