Luigi Pio Di Noia

Controlled Fault-Tolerant Power Converters for Power Quality Enhancement

Power quality depends generally on the interaction of electrical power with electrical equipments. If electrical equipments operate correctly and reliably without being damaged or stressed, a suitable level of power quality is assured. On the other hand, if the electrical equipment malfunctions, is unreliable, or is damaged during normal usage, power quality is poor and probably the economical loss could be important like the technical one. In the scenario of the Distributed Generation, power quality issues will be moreover important because an higher dissemination of power conditioning equipment will be requested and this obviously increases the sources of vulnerability of the electrical system. In this paper fault tolerant power converters are considered as a viable solution of power quality problems and a suitable control algorithm of them is presented. The control proposed in the paper is based on the model of the power converter reformulated in terms of healthy leg binary variable and the paper shows how this control is able to save the aspect of power quality when the converter works in the linear range. The effectiveness of such an algorithm and of the fault tolerant power converters are finally verified by means of simulations.

Functional integration of electric vehicles within the energy supply network

The Electric Mobility mandate will bring user friendly means and solutions to the transport system that safeguard energy resources, human health and environment. Considering that electricity is the most advantageous and effective vector for well to wheel energy convey, the maximization of the range of the electric vehicle with minimum amount of energy, postulates the analysis of the system vehicle - energy supply infrastructure to define the modes of the energy transfer to the vehicle for the accomplishment of its daily mission. The consideration of the location of the energy transfer points on the road, besides the basic facilities for overnight battery charging, with the support of an E-Mobility management for connection with user and with grid for the negotiation of the most appropriate site and time for energy transfer, even bi-directionally, could be a way to define the storage system design to be integrated to the vehicle. Factors such as the type, the size and the weight of the battery, including the cost and the impact on energy, environment and human health are of increased importance to the holistic design of the system. Basic pillars for the analysis are being produced by the studies conducted in the European programs (e.g. EV-CONNECT, FABRIC and others, which are described in the paper) dealing with the network of energy supply infrastructure and the technology for the power transfer. A breakthrough element in this scenario is the wireless power transfer by magnetic field, from the road infrastructure to the vehicle, which is object of study and development in the FABRIC Project, for possible application with interoperability in static and dynamic mode of operation. This concept, with the ICT communication support and the E-Mobility Management interaction can open the way to the ultimate consequences of the optimization of the system vehicle-infrastructure in terms of application diffusion, minimization of on board storage demand and global energy effectiveness.

Mathematical Model of a PM Brushless Motor with Different Stator-Rotor Pole Pairs Number

The paper presents a mathematical model of Permanent Magnet AC brush less machines (PMSM) having a number of stator poles-obtained via the distribution of the three-phase winding- different from the rotor one, realized by the displacement of the permanent magnets. For these so-called Fractional-Slot motors (where few total slots generate high equivalent number of poles) the available mathematical models appear partial and/or incomplete, despite of numerous designing considerations made in literature. In this paper an analytical approach is developed to point out an instantaneous-values mathematical model with concentrated parameters, that can be suitable for control architecture systems when some simplification hypotheses are added. The model takes into account a general distribution of the armature magneto motive force field, and the total harmonic content of the rotor flux density. The whole MMF harmonic content is then properly reduced and the result is compared to a traditional PMSM model.

Integral sliding-mode direct torque control of sensorless induction motor drives

The paper deals with a full sliding mode approach for induction motor drives direct torque and flux control. The proposed solution is composed by an integral sliding-mode control and by a speed-sensorless sliding mode observer. The suggested Integral Sliding-Mode Direct Torque Control (ISMDTC) is formulated in the stator flux reference frame, without employing current regulators. The adopted sliding mode observer provides stator-flux and torque estimation, without rotor-speed adaptation. The numerical results show that the ISMDTC maintains the robustness of the sliding controller, reducing the chattering during the steady state. Moreover, it consents to achieve similar performance like more complex second-order SMC offering more simple implementation. The ISMDTC assures good accuracy and robustness to parameters deviations at low-speed operations as well as in all the operative range of the IM drives. For proving the goodness of the proposal the suggested control is also compared with a conventional DTC control.