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This paper deals with the optimal fault-tolerant operation of a 5-phase permanent magnet (PM) brushless DC (BLDC) drive. In particular, the companion paper (Part I) proposes the optimization of the current supply to obtain the maximum power in healthy conditions and its analytical solution. In the present paper (Part II), by constraining the proposed model with healthy and fault specific conditions, the magnitude schedule of the currents in the surviving phases is determined in order to obtain the maximum average power and the optimization problem is solved through a numerical approach. In all cases the solution is compared with the one obtained with a “Maximum Torque Per Ampere” criterion.

The computation of end-coil leakage inductances of electric machines is a challenging task due to the complicated leakage flux 3-D distribution in the winding overhang region. In this paper, the problem of computing the field-circuit leakage inductance of round-rotor synchronous machines is addressed. The proposed method is fully analytical and descends from the symbolical solution of Neumann integrals applied to the computation of self-inductance and mutual inductance combined with the method of mirror images to account for core effects. With respect to existing analytical approaches, the methodology requires neither numerical integral solutions nor discretizing the end-coil geometry into small straight elements. The accuracy of the proposed technique for computing the mutual inductance between two single-end turns is assessed against measurements on a dedicated experimental setup. The extension of the method to the computation of the entire field-circuit end-coil leakage inductance is assessed by comparing with the 3-D finite-element analysis.

The complex relative permeance function is a useful mathematical tool to study the magnetic field of electric machines with slotted air gap. In the literature, the complex permeance function is usually identified by means of numerical techniques based on conformal mapping. In this paper an alternative analytical approach is proposed. The method is based on solving the magnetostatic differential field equation over a portion of the slotted air gap by imposing suitable boundary conditions in the slot opening region. Such boundary conditions exploit the mathematical law which governs the divergence of the magnetic field in the neighborhood of corner-shaped ferromagnetic regions. Furthermore, the results of Carter theory on slot fringing effects on the air gap field are used. A simple easy-to-compute formula is obtained for the complex permeance function. Its accuracy is assessed by comparison with Finite Element Analysis (FEA).

Induction motors are presently the most widespread kind of electric machinery used in industrial and vehicle applications. In the engineering practice, it frequently happens that designers or final users have to roughly estimate the size, weight and some basic performance data of an induction motor based on few specification requirements such as its rated speed and power. This paper describes a heuristic approach which can help make a first-attempt dimensioning in an approximate but reliable way. The method uses homothety as the theoretical basis and derives practical laws by identifying homothetic law parameters through the statistical analysis of a set of sample built machines. The results obtained are compared to those derived from classical books showing significant discrepancies which fully justify the adoption of more sophisticated heuristic models as those being presented.