Analysis and design of fault tolerant axial flux permanent magnet synchronous motors

by Harold Saavedra Ordóñez

Institution: Universitat Politècnica de Catalunya
Year: 2015
Record ID: 1128799
Full text PDF: http://hdl.handle.net/10803/286323


Electric vehicles (EVs) are attractive comparted to internal combustion engine powered vehicles due to several benefits, including low emissions, higher efficiency, less maintenance costs, stronger acceleration or lower fuel price, among others. EVs require traction motors with especial features, including high efficiency, high power and torque density, compactness, precise torque control, extended speed range. This work focuses on the analysis and optimal electromagnetic design of fault tolerant permanent magnet synchronous motors. The study is mainly based on the research of analytical design procedures and the effect of electrical faults in the motor behavior, according to the configurations of each machine. The study will be developed by using analytical tools, and validated by applying 2-D and 3-D finite element methods (FEM). A brief study about the main achievements regarding the design of fault tolerant machines is made, identifying the possible improvements and main rules of design in this kind of machines. Then a study focused on the requirements of a fault tolerant design is made, in order to select the appropriate motor configuration. Since the consequences of inter-turn faults can be catastrophic in PMSMs, chapter 3 studies the influence of the winding configuration on the detection of such faults. This detection is based on the analysis of the stator currents and the (zero-sequence voltage component) ZSVC spectra. Several types of winding configurations are selected for analysis i.e. fractional- and integral-slot windings, overlapping- and non-overlappingwindings, single- and double-layer, full- and short-pitch, constant- and variable-pitch windings. Taking into the fault tolerant tendencies about the redundancy of the system, the study of the effect of inter turn fault is extended to the five phase machine, thus a parametric model of the five-phase PMSM is developed, this model accounts for the effects of inter-turn faults. This parametric model is used to select the harmonic frequencies to be studied to detect such faults. Likewise, the amplitudes of these harmonic frequencies are further analyzed by means of FEM simulations, therefore showing the potential of the proposed system to detect inter-turn faults in their early stage, which is a desirable characteristic for a fault tolerant system. The demagnetization effect on AFPMM torque is also analyzed. The main objective was to study the influence of the magnet shape in the performance of an AFPMM working under faulty condition, in order to select the most suitable type of magnet for the design of a fault tolerant machine. After an exhaustive analysis of the main electromagnetic faults on PMSMs, the work is focused on the optimal electromagnetic design of an AFPMM. The optimal design is based on a set of analytical equations whose accuracy is validated by means of FEM simulations. Next, to find the optimal solution, the huge set of possible motor solutions is explored by means of computationally efficient optimization algorithms leading to an optimum…