Azeez, Najath Abdul
Multilevel inverters are very popular for medium and high-voltage induction motor (IM) drive applications. They have superior performance compared to 2-level inverters such as reduced harmonic content in output voltage and current, lower common mode voltage and dv/dt, and lesser voltage stress on power switches. To get nearly sinusoidal current waveforms, the switching frequency of the conventional inverters have to be in¬creased. This will lead to higher switching losses and electromagnetic interference. The problem in using lower switching frequency is the introduction of low order harmonics in phase currents and undesirable torque ripple in the motor. The 5th and 7th...
Ferroﬂuids are stable colloidal homogeneous mixtures of nano-size single-domain ferromag¬netic particles covered by surfactant layer, and suspended in a carrier ﬂuid compatible with the surfactant. Physical properties of ferroﬂuid allows one to control it externally using magnetic ﬁeld without being in direct contact with it. The thesis presents a novel mechanism to pump ferroﬂuid based on the principle of variable reluctance, in an external magnetic ﬁeld.
The static and dynamic pressure behavior of ferroﬂuid in a switched DC magnetic ﬁeld gives an insight into the variable reluctance behavior of ferroﬂuid. A ferroﬂuid pump based on the prin¬ciple of variable reluctance...
Kaarthik, R Sudharshan
MULTILEVEL inverters are the preferred choice of converters for electronic power conversion for high power applications. They are gaining popularity in variety of industrial applications including electric motor drives, transportation, energy management, transmission and distribution of power. A large portion of energy conversion systems comprises of multilevel inverter fed induction motor drives. The multilevel inverters are ideal for such applications, since the switching frequency of the devices can be kept low. In conventional two level inverters, to get nearly sinusoidal phase current waveform, the switching frequency of the inverter is increased and the harmonics in the currents are pushed higher...
Experience Mapping based Prediction Control (EMPC) is a new type of controller presented in literature, which is based on the concept of Human Motor Control (HMC). During the developmental phase, called the initial learning phase, the controller records the experience in a knowledge base, through online interactions with the system to be controlled. This knowledge base created using the experience maps is termed as Experience Mapped Knowledge Base (EMK). The controller envisages the development of EMK only through interaction with the system, without the need for knowledge of the detailed plant model. The EMPC controls the system through prediction of...
Eddy current (EC) based testing and measurement methods are well known in non-destructive testing (NDT) world. EC sensors are extensively studied and used for material health monitoring and its property measurement. Target displacement measurement is one of the well-known applications of EC method. The main advantage of EC sensor is its working capability in harsh environment like humidity, contamination etc. It is non-contact, rugged and requires less maintenance. The range and sensitivity of target displacement is mainly determined by the probe geometry and its construction method. Also displacement measurement depends upon geometry and electromagnetic (EM) properties of the target plate....
Mahale, Gopinath Vasanth
Face recognition is a field of biometrics that deals with identification of subjects based on features present in the images of their faces. The factors that make face recognition popular and favorite as compared to other biometric methods are easier operation and ability to identify subjects without their knowledge. With these features, face recognition has become an integral part of the present day security systems, targeting a smart and secure world.
There are various factors that de ne the performance of a face recognition system. The most important among them are recognition accuracy of algorithm used and time taken for...
MU LT I L E V E L inverters are becoming the preferred choice for medium voltage high power applications. Multilevel inverters have a number of inherent advantages over conventional two level inverters. The output voltage has multiple steps or levels, resulting in reduced dV/dt, which leads to lower electromagnetic interference, making it easier to meet electromagnetic compatibility (EMC) regulations. Multilevel inverters have a much lower effective switching frequency, which leads to a reduction in switching losses. The output voltage of multilevel inverters has a much lower harmonic content. In applications such as power conversion or grid-connection, filters need to...
Social networks play an important role in disseminating a piece of information in a population. Companies advertising a newly launched product, movie promotion, political campaigns, social awareness campaigns by governments, charity campaigns by NGOs and crowd funding campaigns by entrepreneurs are a few examples where an entity is interested in disseminating a piece of information in a target population, possibly under resource constraints.
In this thesis we model information diffusion in a population using various epidemic models and study optimal campaigning strategies to maximize the reach of information. In the different problems considered in this thesis, information epidemics are modeled as...