ETD

Archivio digitale delle tesi discusse presso l'Università di Pisa

Tesi etd-01302018-154847


Tipo di tesi
Tesi di laurea magistrale
Autore
MAMBOU NOUMBI, ERIC
URN
etd-01302018-154847
Titolo
DEFINIZIONE DELL'ARCHITETTURA DI CONTROLLO PER MOTORI BRUSHLESS PER DRONI AD ELEVATA AFFIDABILITA
Dipartimento
INGEGNERIA DELL'ENERGIA, DEI SISTEMI, DEL TERRITORIO E DELLE COSTRUZIONI
Corso di studi
INGEGNERIA ELETTRICA
Relatori
relatore Sani, Luca
Parole chiave
  • PI
  • architettura di controllo
  • ridondante
  • droni
  • architettura di controllo
  • permanent magnet synchronous motor
  • double star PM machine
  • macchine sincrono 6 fasi
  • guasto
  • motore 5 fasi
  • multifase
  • park
  • park inversa
  • elevata affidabilità
  • DTC(direct torque control)
  • FEM
  • halbach
  • fault-tolerant
  • PMSM
  • FOC(field oriented control)
  • motori PMSM multifase
  • brushless
Data inizio appello
19/02/2018
Consultabilità
Completa
Riassunto
Multi-phase permanent magnetic synchronous motors (PMSM) are used in locations that require fast torque response and high-performance machine operation. The Field Oriented Control ‘’FOC’’ and Direct Control Torque “DTC’’ control technology were used to check the torque and engine flow values. The FOC allows to maintain the nominal field flow over the entire load range to obtain the best transient response instead of the DTC controlling the voltage source inverter states based on the difference between the required torque and flow values and obtained. This is done by selecting one of the twelve voltage vectors obtained from the inverter to have fluctuations in torque and flow between the hysteresis band limits. The field of "fault-tolerant" applications is certainly among the most innovative fields of modern research on electric motors, as it leaves much more freedom in design and allows the exploration of new solutions. The reduction in the cost of permanent magnets and control systems has allowed the development of new permanent magnet solutions with fractional windings. The reliability of these motors makes them particularly suitable for those "safety critical" applications where system failure cannot be tolerated and mechanical or electrical redundancy is required. In this paper we focused on possible design solutions, fixed on multi-phase permanent magnet synchronous (PMSM) motors, which are characterized by a high "Fault-tolerant capability", allowing the machine to operate in fault conditions. In fact, each phase makes a contribution with respect to the total torque. Different solutions have been proposed to maintain an acceptable behavior under fault conditions; here possible design configurations will be presented, ie 5-phase and 6-phase PMSM machines. Based on one of these possible configurations we proceed to the sizing and analysis of that engine. It has become clear that the most successful design approach involves a multi-step drive where each phase can be considered as a single module. The operation of any module must have a minimal impact on others, so that in case of failure of that module, others can continue to operate without suffering consequences. The modular approach requires that there is minimal electrical, magnetic, and thermal interaction between the converter phases. The "Flux-Switch" permanent magnet synchronous machines (FS-PMSM) have recently established themselves as an attractive type of machine for their high torque densities, simple and robust rotor structure, and the fact that permanent magnets and coils they are both on the stator. The Flux-switch permanent magnet synchronous machines (FS-PMSM) are a relatively new type of "Brushless PM Stator" machine. They have interesting advantages including high torque capacity and high power, essentially sinusoidal back-EMF waveforms, as well as having a compact and robust structure due to both the position of the magnets and the stator windings instead of the rotor like those in conventional rotor-PM machines. The comparative results between a FS-PMSM and a traditional surface-mounted PM (SPM) motor with the same specifications reveal that FS-PMSM has a higher airflow density, a higher torque for copper loss, but also a greater ripple torque due to pair-cogging. However, for only the permanent magnet excited machines, it is a traditional contradiction between the demands for high torque capacity under the base speed (constant torque region) and the high speed above the base speed (constant power region) especially for hybrid vehicle applications. A new type of fault tolerant FS-PMSM unit is presented that is able to function when at least one of the windings is faulty or in the presence of a short-circuit. The scheme is based on a double winding motor provided by two separate voltage controlled inverters. The windings are arranged in such a way as to form two independent and isolated sets. The simulation and experimental work will describe in detail the performance of the engine during both healthy and defective scenarios, including short-circuit failures and will show the robustness of the converter able to operate under these conditions.
The thesis is part of the project of control architecture for drones with high reliability for brushless motors (PMSM), modeling and sizing with the model of park axis d-q to be applied to synchronous machines with permanent double-magnet magnets with internal magnets, implementation of control model: "Field Oriented Control" (FOC) with hysteresis and "Direct Torque Control" (DTC) of the engine that allows landing in case of engine failure all using Matlab / Simulink. The effectiveness of the proposed modeling method is verified by comparing the results relative to the measurements on a test machine and simulation data.
This project was carried out in the laboratory of the Department of Energy, Systems, Territory and Construction Engineering (D.E.S.Te.C.) of the University of Pisa.
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