A fully integrated board for resolver-to-digital conversion is proposed in this paper. It is based on a combined analog/digital circuit, which allows one to track the shaft angle of a standard resolver in a digital form. Furthermore, the board also provides the feeding signal for the resolver-rotor circuit. All the tuning and configuration settings, which allow one to adapt different kind of resolvers to the proposed system, can be easily implemented directly on the board. The final assembly is a compact low-cost resolver-to-digital converter. The entire board design and implementation are described in this paper. In addition, several tests at different resolver speeds have been performed for validation.

This work deals with a 10-MW doubly fed induction generator (DFIG) for direct-drive operation of wind turbines with a reduced-size converter. The work includes a lumped parameter design, an optimization procedure, a finite-element analysis (FEA), and an electrical performance assessment. A monetary cost was assumed as a cost function, and an approximation of the construction cost as a function of the axial length was obtained. The found solutions were checked by FEA in order to assure the mechanical feasibility. Further verifications were developed to allow a conclusive performance evaluation. The optimization improved the cost of the proposed DFIG, including materials, losses, and converter, making it slightly cheaper than an available permanent-magnet synchronous generator.

A predictive algorithm is presented in this paper, which allows the compensation of the dead-time effects in a voltage-source inverter feeding an induction motor, with space-vector pulsewidth modulation. It is based on the modification of the reference space vector of the feeding voltage according to a step-by-step analytical prediction of the stator phase currents. In this way, the effects of the dead time can be taken into account and compensated. The validity and feasibility of the proposed algorithm are confirmed by simulation and proved by experimental implementation.

Marine energy represents a very promising source of energy available worldwide. Although this energy is available in several forms, wave energy is the more widespread source characterized by high power density. In order to exploit energy from waves, numerous systems have been designed and commercialized. The Inertial Sea Wave Energy Converter is a device based on a floating body slack-moored to the seabed, using a gyroscope as a reference frame to produce electric power. This paper describes the design of the proposed converter equipped with two linear tubular permanent-magnet generators, exploiting the reciprocating motion between the gyroscopic system and the hull to generate power. The design of a two-phase linear tubular generator is analyzed. Experimental tests on a scale prototype have been performed.

The performance of Voltage Source Inverter (VSI) is affected by power semiconductor nonlinearities, dead time, and control delay. The compensation of these nonlinear effects is necessary to meet requirements in terms of current quality and high efficiency, especially for grid-connected power conversion systems. In this paper, the effects of nonlinearities are widely analyzed and a new compensation technique for a steady-state current-controlled VSI is proposed. It is based on a step-by-step voltage compensation on the basis of the current error evaluated within each control interval. As a result, a complete compensation is achieved within a whole period of the fundamental. To cope with the zero-current clamping effect, the proposed compensation technique is implemented in a recursive way. For slow-dynamic applications, such as photovoltaic systems, this method allows achieving high performance with very low computational requirements.

Failure of a phase current sensor in permanent magnet synchronous machine (PMSM) drive can highly impact the performance of the drive. Especially, offset faults can cause torque oscillations, which can lead to an unacceptable deterioration of the drive's performance and mechanical damages. The diagnosis of this fault condition is of fundamental importance in many applications and it is often solved by means of highly computational state estimation techniques. This article presents a new model-based approach to systematically and accurately detect and estimate phase current sensor offsets in PMSM drives. The steady-state analytical solution of the PMSM drive model, including the control loop of the field oriented control and the sensor offset disturbance, has been found, allowing for estimating the effect of the fault on the electric drive performance. Then, a simple and effective diagnostic algorithm has been developed to detect, isolate, and accurately estimate the location and the magnitude of the fault eliminating any need for state estimation or observers. Numerical and experimental results have been reported to validate the proposed model and diagnostic algorithm even in case of motor parameters variation.