Two alternative modes of operation for the current-source flyback inverter are investigated in this paper. The discontinuous conduction mode (DCM), where a constant switching frequency (CSF) control method is applied, and the boundary between continuous and DCM (BCM) that is introduced for photovoltaic (PV) applications in this paper (where a variable switching frequency control method is applied). These two control methods are analytically studied and compared in order to establish their advantages as well as their suitability for the development of an inverter for decentralized grid-connected PV applications. An optimum design methodology is developed, aiming for an inverter with the smallest possible volume for the maximum power transfer to the public grid and wide PV energy exploitation. The main advantages of the current-source flyback inverter are very high-power density and high efficiency due to its simple structure, as well as high-power factor regulation. The design and control methodology are validated by personal computer simulation program with integrated circuit emphasis (PSPICE) simulation and experimental results, accomplished on a laboratory prototype.

Active clamp topologies of low power dissipation have become a very attractive solution in order to limit overvoltages in flyback converters. Although many suitable topologies have been introduced for the case of discontinuous conduction mode (DCM), where the duty cycle value depends on the load level, in continuous conduction mode (CCM) it is more difficult to appropriately design such topologies so as to "sense" load changes-due to the small duty cycle divergence under wide load variation. Taking for granted that in order to achieve high power-factor correction in these converters, CCM is a more attractive mode of operation, a drastic solution for this case that will manage to eliminate voltage stresses under wide load changes has become very essential. For this purpose, this paper presents an active clamp topology with small power dissipation, suitable for flyback converters operating in CCM mode. Its main idea is the use of a load-dependent current source, consisting of an auxiliary converter operating in DCM mode. Experimental results highlight the effectiveness of the proposed topology under wide load changes, establishing it as an appropriate solution in order to develop flyback converters, even at the power range of 500 W.

The newest technology on decentralised grid-connected PV systems is the "AC-PV Module", which is characterised by a number of clear advantages over conventional large PV systems. Single stage topologies seem to be a rather attractive solution, for these applications, since in generally they are characterised by high efficiency, low cost and simple structure with high reliability due to reduced components count. On the other hand in single-phase AC-PV Module inverters, the power that is transferred to the power network has a large amount of power pulsation at twice line frequency. So a large ripple of voltage and current appears at the PV module output. Taking into account that there is a close correspondence between the power that flows from a PV module and the point of operation, this fact leads to reduced PV power generation. In order to overcome this defect, this paper presents a novel current pulsation smoothing parallel active filter (CPS-PAF) which is independent from the inverter topology and his operation mode. Purpose of the proposed CPS-PAF is the elimination of the low frequency PV current ripple. So the PV module can be operated close enough to the maximum power point and consequently the PV generated electricity power is maximised. The CPS-PAF conception, control and effectiveness are validated by PSpice simulation and experimental results accomplished on a laboratory prototype.

Nowadays, the imperative need for the reduction of Greenhouse Gas (GHG) emissions leads to the wider adoption of environmentally friendly transportation means. As a result, various policies underpinning the Electric Vehicle (EV) deployment are legislated globally, and several technical advances contributing to the electrification of the transportation sector are pursued. In this paper, a comprehensive overview of the current status of the infrastructure utilized for the realization of both conductive and contactless (wireless) charging of an EV battery is conducted. Furthermore, the issue of EV integration in conventional distribution networks, as well as in future power system architectures, is discussed in detail. Particular focus is given to wireless (i.e., inductive) charging. A detailed presentation of the respective standards and charging levels, as well as the magnetic couplers and the compensation network configurations, is carried out. Moreover, innovative concepts such as dynamic and quasi-dynamic wireless charging, as well as future challenges and opportunities, are presented and discussed. Finally, smart control and communication techniques applicable to EV charging are presented in the context of the future Internet of Energy (IoE) concept.

An innovative design methodology that optimizes the weighted efficiency of a single-phase, single-stage flyback inverter for ac-photovoltaic (PV) module applications is proposed. This novel approach combines the essential advantages of the flyback topology with high-efficiency design in the direction of a reliable, cost-effective, and high-performance PV system. The proposed methodology focuses exclusively on choosing the inverter design parameters, taking into consideration the PV module characteristics and the topology operation constraints. In order to meet this goal, an analytical losses calculation should be performed. Since the problem is complicated, special effort is given to manipulate the equations and variables in such a way to minimize the number of parameters. The proposed methodology is also verified experimentally.