Conventional magnetically coupled resonant wireless power transfer systems are faced with resonant frequency splitting phenomena and impedance mismatch when a receiving coil is placed at misaligned position. These problems can be avoided by using uniform magnetic field distribution at receiving plane. In this paper, a novel 3D transmitting coil structure with improved uniform magnetic field distribution is proposed based on a developed optimization method. The goal is to maximize the average magnetic field strength and uniform magnetic field section of the receiving plane. Hence, figures of merit (FoM1 and FoM2) are introduced and defined as product of average magnetic field strength and length or surface along which uniform magnetic field is generated, respectively. The validity of the optimization method is verified through laboratory measurements performed on the fabricated coils driven by signal generator at operating frequency of 150 kHz. Depending on the allowed ripple value and predefined coil proportions, the proposed transmitting coil structure gives the uniform magnetic field distribution across 50% to 90% of the receiving plane.

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The paper presents an experimental and numerical investigation carried out on a ferroresonant circuit in order to determine to what extent the initiation of ferroresonance depends on initial conditions and phase shift. The range of voltage source values at which the initiation of ferroresonance depends on initial conditions and phase shift is named as a possible ferroresonant range, and is determined numerically and experimentally.

Energy harvesting methods provide very low instantaneous power. Accordingly, available voltage levels are low and must be increased so that an energy harvesting method can be used as a power supply. One approach uses charge pumps to boost low AC voltage from energy harvester to a higher DC voltage. Characterized by very low output current and a wide span of operating frequencies, energy harvesting methods introduce a number of limitations to charge pump operation. This paper describes and models behavior of Dickson charge pump in energy harvesting applications. Proposed Energy Harvesting model is evaluated and compared with Standard and Tanzawa charge pump models and with measurement results. Based on the proposed model, the conditions that need to be satisfied so that a charge pump can reach maximum power point of energy harvesting system are defined. Parameter selection method optimized for maximum power point is presented and is experimentally validated.

With advances in Information and Communication Technologies (ICT) in convergence with blockchain technology, cities have been given the opportunity to improve their services, efficiently use resources, and, thus, become Smart Cities. The main properties of blockchain technology like decentralization, immutability, transparency, consensus, and robustness are qualities needed for Smart City. In this paper, we propose a digitalization strategy for the City of Osijek. Smart City digitalization strategy aims to solve problems of emerging urbanization, improve administration by reducing energy and water consumption, carbon emissions, pollution, and city waste management. To develop an information system based on blockchain technology, the administration structure and the current state of information systems are analyzed, and new solutions are presented.