Investigation of Various Laminating Materials for Interior Permanent Magnet Brushless DC Motor for Cooling Fan Application

Permanent magnet brushless DC motors are used for various low-power applications,namely domestic fans,washing machines,mixer grinders and cooling fan applications.This paper focuses on selecting the best laminating material for the interior permanent magnet brushless DC(IPM BLDC)motor used in the cooling fan of automobiles.Various laminating materials,namely M19-29GA,M800-65A and M43,are tested using finite element analysis.The machine's vital performance metrics,namely the stator current,torque ripple,and hysteresis loss were analyzed in selecting the laminating material.The designed motor is also modelled as a mathematical model from the computed lumped parameters.The performance of the machines was validated through electromagnetic and thermal analysis.

A Novel Multilevel Inverter Employing Additive and Subtractive Topology

As the demand for high voltage, high power inverters are increasing and there is a problem of connecting a power semiconductor switch directly to a high voltage network. As a part of this the multilevel inverters had been introduced. As a part of this, several researches had been done for the development of multilevel inverters. The commercially available and extensively studied topologies for multilevel voltage output are Neutral Point Clamped (NPC), Cascaded Half Bridge (CHB) and Flying Capacitor (FC) converters. However, with these existing topologies, there is a significant increase in the number of power switches and passive components. Thus it leads to more complex control circuitry and overall cost of the system increase with increase in the output levels. In this paper, a novel multilevel inverter is proposed in which it employs additive and subtractive topology to get higher output levels. This approach significantly reduces the number of power switches needed as compared to existing topology. The present developed multilevel inverter can generate only five voltage levels. With this proposed topology the multilevel inverter can be modified to nine-level inverter. Moreover modified hybrid multicarrier Pulse Width Modulation (PWM) technique can be implemented in the proposed multilevel inverter in order to obtain uniform switch utilization and lower THD. An appropriate modulation scheme is presented and also the proposed concept is analyzed through simulation studies.

Effect of nanoparticles on the performance of magnetorheological fluid damper during hard turning process

Magnetorheological(MR)fluid damper which allows the damping characteristics of the damper to be continuously controlled by varying the magnetic field is extensively used in metal cutting to suppress tool vibration.Even though magnetorhelogical fluids have been successful in reducing tool vibration,durability of magnetorhelogical fluids remains a major challenge in engineering sector.Temperature effect on the performance of magnetorhelogical fluids over a prolonged period of time is a major concern.In this paper,an attempt was made to reduce temperature and to improve viscosity of magnetorhelogical fluids by infusing nanoparticles along with MR fluids.Aluminium oxide and titanium oxide nanoparticles of 0.1%and 0.2%concentration by weight were considered and experimental tests were conducted to study the influence of nanoparticles on the performance of magnetorheological fluid.From the experimental results it was observed that the presence of nanoparticles in MR fluid reduces temperature and increases the viscosity of MR fluid thereby increasing the cutting performance during turning of hardened AISI 4340 steel.