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A novel approach of exploiting the stator-temperature-monitoring system to perform sensorless rotor-position estimation is described in this paper. The rotor position is, in fact, estimated by processing the voltages induced in thermistor cablings, which are modified in order to work as search coils (SCs). Using SCs, some typical drawbacks of sensorless position-estimation techniques based on the manipulation of fundamental components of stator voltages and currents, such as those related to inverter non-linearities, stator-resistance voltage drops, magnetic saturation and cross-coupling, can be overcome or mitigated. According to the proposed approach, a rotor-position-tracking technique for synchronous reluctance motor drives is developed independently from motor parameters. Such a sensorless rotor-position-estimation technique can be directly used to build up a sensorless controller or to improve the performance of conventional model based sensorless control systems. Simulations and experimental tests confirm the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

The paper deals with the analysis and implementation of a vector control strategy devoted to integrated multidrive systems used in starter alternator applications with several dc buses at different voltage levels. The electromechanical system of the considered multidrive topology is obtained by splitting the conventional stator winding of an induction machine into different n three-phase subunits, maintaining the same magnetomotive force distribution and sharing the same rotor. Each stator unit together with rotor can be considered a submotor, thus the entire electromagnetic system behavior can be considered as the combination of all submotors contributions. The submotors are suitably supplied through standard three-phase inverters whose technical specifications are also established according to the storage unit voltage levels. First, a detailed mathematical representation of the electromagnetic system has been developed, then the conditions to carry out the field orientation in each generic subdrive are determined. Addressing a starter-alternator system, the integrated multidrive configuration has been experimentally tested, highlighting the capability of the proposed approach to efficiently handle multidirectional power flows among the storage units and mechanical system while ensuring high dynamic performance. [ABSTRACT FROM AUTHOR]

Due to their inner structural redundancy, ac multidrive systems (MDSs) can achieve a fault-tolerance capability with minor circuit modifications. However, some additional components are generally required in order to create emergency current paths. According to a recently presented approach, the amount of additional components can be reduced by exploiting healthy drives to support faulty drives. This can be obtained by connecting together the neutral points of motor stator windings and suitably sharing the neutral current of faulty units among some, or all, healthy units. Following such an approach, three current-sharing methodologies for fault-tolerant MDSs are presented in this paper, which are able to cope with single or multiple failures. They are first theoretically introduced and then validated by mean of simulations and experimental test results. [ABSTRACT FROM PUBLISHER]