Buck, boost, and buck-boost converters constitute large class of dc-dc converters used in practice and are interesting nonlinear dynamical systems. It has been shown earlier that various nonlinear phenomena including subharmonics and chaos can be observed in these converters. In this paper we show that with the simplifying assumption that voltage regulation is achieved in high frequency modulat...

Fuel cells are new alternative energy resource that has a great promise for distributed generation and electric vehicle application. However, fuel cells have a slow response due to their slow internal electromechanical and thermodynamic response. To optimize the fuel cell system performance, a fuel cell DC-DC converter with an appropriate controller which can regulate the power flow and automat...

The goal of this work is to reduce the DC-link capacitance of a two-stage single-phase inverter so much that the use of film capacitors becomes feasible in both, price and volume. Film capacitors instead of electrolytic capacitors could increase lifetime and reliability of the inverter, especially in high-temperature applications like module-integrated micro-inverters. For the capacitance reduc...

A novel bidirectional DC-DC converter is presented in this paper. The circuit configuration of the proposed converter is very simple. The proposed converter employs a coupled inductor with same winding turns in the primary and secondary sides. In step-up mode, the primary and secondary windings of the coupled inductor are operated in parallel-charge and series-discharge to achieve high step-up ...

ARTICLE INFO ABSTRACT ARTICLE HISTORY: Received 15 September 2012 Revised 15 August 2013 Accepted 22 August 2013 This paper presents a novel control method to improve the efficiency of low-voltage DC-DC converters at light loads. Pulse Width Modulation (PWM) converters have poor efficiencies at light loads, while pulse frequency modulation (PFM) control is more efficient for the same cases. Swi...

Sensors with long lifetimes create new applications in medical, infrastructure and environmental monitoring. Due to volume constraints, sensor systems are often capable of storing only small amounts of energy. Several systems have increased lifetime through VDD scaling [1][2][3]. This necessitates voltage conversion from highervoltage storage elements, such as batteries and fuel cells. Power is...

The energy efficiency, greenhouse gas (GHG) emissions, and carbon efficiency of paddy rice production were analysed in Sari in the Mazandaran province of Iran during 2011–2012. Data was collected through questionnaires and interviews with paddy producers. The results showed that the net energy gain was 27,932 MJ ha-1 and energy efficiency was 1.83 during production. The results o...

Since the discovery of dendritic cells (DCs) by Ralph Steinman and Zanvil Cohn 40 years ago (1), the role of these cells as critical regulators of immune tolerance versus activation has emerged as one of the most fundamental concepts in the field of immunology. Serving as a link between the innate and adaptive immune systems, DCs exhibit sensitive immune surveillance capabilities that enable th...