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This paper analyzes the performance of a gridtied, wide power range, transformerless, modified threephase Current Source Inverter (CSI), named CSI7. The CSI7 topology is here analyzed along with a suitable Space Vector Modulation (SVM) strategy able to attenuate the excitation of the output CL filter. The theoretical analysis and simple analytic expressions highlighted the performance and limitations of the topology when employed as a singlestage PV inverter, with particular emphasis on injected grid currents distortion and ground leakage current values. The inverter wide input range allows interfacing PV strings of different module count with a simple closed loop control. The principle of operation and control is described, the viability of the CSI7 topology was assessed with simulations and extensive experiments on a full-size laboratory prototype.

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This paper focuses on modeling and experimental validation of a diagnostic fault classification procedure for interturn fault detection in permanent-magnet (PM) multiphase machines designed for fault-tolerant electric drives. The diagnostic procedure is based on the symmetrical component theory and relies upon the combined space vector D that gathers information from the two original space vectors obtained with different reference frames. The diagnostic index effectiveness and robustness were also investigated against other fault types such as rotor eccentricities and magnet damage to assess its discrimination capability. The proposed procedure was experimentally evaluated for the interturn fault case on a five-phase PM machine. Experiments were carried out at different speed and load levels, with increasing numbers of short-circuited turns. Both simulation and experimental results demonstrated the feasibility of the proposed diagnostic method.

This paper presents simple and effective control strategies for the active rectifier stage (AC/DC stage) of a grid-connected low power system for micro wind applications employing Permanent Magnet Synchronous Generator (PMSG). In particular a novel algorithm for the estimation of the rotor angle of the PMSG, based on flux estimators, was implemented using an adaptive low-pass filter coupled with a feed-forward compensator. This enabled a very smooth start-up operation of the PMSG, obtained by pre-loading the values of the flux\ud estimator and using a single voltage transformer (VT) transducer. The solution for the power flow control between the active rectifier and the other(s) power converters connected to the common DC link was implemented without any digital communication between them, in order to obtain a solution suitable for modular architectures (e.g. to be used in conjunction with a grid-connected converter and/or an energy storage system). Simulation and experimental results confirmed the effectiveness of the proposed solutions. The experimental validation was conducted using a grid-connected converter as load for the proposed active rectifier

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The most common topology for micro wind turbine systems is composed of the wind turbine directly connected to a Permanent Magnet Synchronous Generator (PMSG) followed by a AC/DC/AC converter. The converter is realized with a AC/DC passive rectifier, a DC/DC boost converter and a DC/AC full-bridge inverter which injects the electric power into the grid.Considering the cost reduction of power switches and Digital Signal Processors (DSP), back-to-back inverter topologies have to be considered for new projects, since they allow to obtain better energy productivity of the wind systems.In this paper a complete solution based on back-to-back topology is presented.This solution includes the sensorless vector control for the PMSG, the Maximum Power Point Tracker (MPPT) algorithm, the d-q vector control of the single-phase grid connected inverter and the power flow control strategies from the PMSG to the grid. It is worth noticing that the two full-bridge power converters are controlled by two different DSP which can exchange information only through the value of the DC Link voltage.Experimental results confirm the effectiveness of the adopted solutions.