Analytical Investigation and Control System Set-up of Medium Scale PV Plants for Power Flow Management

In the field of photovoltaic (PV) plants and energy conversion from renewable sources, a large part of the technical literature is more devoted to practical aspects (new solar cells, electrically driven PV panels, safety, reduction of parasitic currents, etc.) than to theoretical investigations. Despite this tendency, this paper presents a mathematical analysis of a medium scale photovoltaic power generation system connected to the distribution network and of its control system. In such a system, the conversion stage is unique due to the absence of a boost chopper. The conducted analysis leads to the interesting conclusion that the inverter used in the plant presents two degrees of freedom, easy to exploit in a control system in which the inverter simultaneously realizes the interconnection to the grid and the MPPT control. The structure of the control system is then presented, discussed and validated by means of numerical simulations

A modular approach in teaching thyristor rectifiers with equation-oriented softwares

This article is devoted to some issues of teaching power electronics in university courses. In the modern education system the students are expected to be no longer subject of passive learning, but that, within a certain extent, they collaborate in their training interactively with the teacher to develop the applications and the topics of the studied framework. For this purpose, this article presents a modular approach for teaching module regarding three-phase thyristor rectifiers

A Software for the Evaluation of Winding Factor Harmonic Distribution in High Efficiency Electrical Motors and Generators.

In this paper a software developed for the determination of winding connections, the calculation of winding factors and the evaluation of their harmonic distribution of three and two phase windings is presented by using as input data simply the number of slots, pole pairs and phases. The software is implemented as a function in MATLAB environment. By means of some examples, covering the most relevant winding types, the capabilities of this software will be shown. Particularly, integer and fractional single and double layer winding can be treated. Some examples are presented and briefly discussed. The connections, the winding factor harmonic distribution, the electro-motive force (e.m.f) THD calculations results are shown together with an example on how is possible to determine the e.m.f. induced in a winding from the air gap flux distribution and to estimate the differential leakage inductance

Analysis, characterization and minimization of IPMSMs cogging torque with different rotor structures

This paper presents the analysis, characterization and comparison of the cogging torque components generated by five different IPMSM rotor structures. More in detail, an IPMSM model (named IPMSM1), which is derived from a commercial geometry, is analyzed by using a Finite Element Method (FEM) approach. Then, four other IPMSM models, which are obtained by modifying the IPMSM1 rotor structure and by maintaining the same stator configuration, are proposed and analyzed. From the obtained simulation results, the cogging torque components for each structure are determined and compared. From this comparison, a significant cogging torque decrease is occurring for the modified geometries, without affecting the values of the generated torque. Furthermore, a meaningful relationship between the peak values of the cogging torque and the gradients of the flux density around the neutral area is reported and discussed. Therefore, simple structure modifications applied to the rotor geometry can bring significant improvements in terms of motor performances and cogging torque reductio

Assisted software design of a wide variety of windings in rotating electrical machinery

In this paper a software developed by the Authors for winding design is presented. In particular, this software can be used as a valid aid in design and analysis for a wide variety of windings with generic number of phases, pole pairs, slot number, etc‥ The calculation of winding factors and the evaluation of their harmonic distribution is also accomplished. The software is implemented in MATLAB® environment. By means of some examples, covering the most relevant winding types, the capabilities of this software will be shown. Particularly, integer and fractional slot, single and double layer winding, concentrated windings, imbrication, belt widening and belt shifting techniques can be treated in order to reduce particular harmonics in the electromotive force (e.m.f) or in the magnetic field (m.m.f.=magneto motive force). Thanks to this software it is possible to determine quickly the winding connections. Moreover, the winding factor harmonic distribution, the THD of e.m.f., the differential leakage and the spatial distribution of the m.m.f. is computed in a very easy way