Feasibility Study of Fault Tolerant Blac Motor Using PM Enhanced Sensing

Abstract

BLAC motor operation requires the application of identical zero crossing higher voltage applied to its winding. This voltage should be greater than the motional induced EMF. It is possible to obtain a replica of motional induced EMF in its winding using Permanent Magnet (PM) enhanced sensing scheme. Any PM rotor having even number of N-S poles may be suitable for such a scheme. In this paper, the feasibility study of a fault-tolerant BLAC motor using PM enhanced has been experimentally investigated. In actual practice input voltage of PM motor contains larger number of harmonics due to switching action thereby making it quite cumbersome to estimate the EMF induced in its coil. In PM enhanced sensing, the replica of induced EMF is available for each coil under dynamic condition. The scheme introduced can be suitably implemented for fault tolerant motor where the motional induced EMF of each of the winding segment of auxiliary winding may be amplified using commercially available Power Operational amplifier (P-OPAMP). The amplified voltage is used to activate the respective winding segment on the main winding.