ii I hereby declare that I am the sole author of this thesis. This is a true copy of the thesis, including any required final revisions, as accepted by my examiners. I understand that my thesis may be made electronically available to the public. Abstract Variable speed drives allow for more precise speed control of induction motors, are of high power factor, and offer fast response characterist...

An important factor in industrial progress during the past five decades has been the increasing sophistication of factory automation which has improved productivity manyfold. Manufacturing lines typically involve a variety of variable speed motor drives which serve to power conveyor belts, robot arms, overhead cranes, steel process lines, paper mills, and plastic and fiber processing lines to n...

---------------------------------------------------------------------***--------------------------------------------------------------------Abstract For providing power from Vehicle to grid, the role of intelligent charger comes in to the action. The intelligent charger for vehicle to grid power flow comprises of AC-DC PWM converter and bidirectional converter. During the onpeak load condition,...

The paper presents design and performance evaluation of two-stage ac adapters for notebook computers which deliver 70 W from the universal line. Three versions of the flyback converter, as well as the PWM and resonant half-bridge converter were evaluated and compared with respect to their efficiency, component stress, output filter size, and complexity.

16 Management Summary One of the driving forces behind the industrial revolution was the invention—more than a century ago—of the electric motor. Its widespread use for all kinds of mechanical motion has made life simpler and has ultimately aided the advancement of humankind. And the advent of the inverter that facilitated speed and torque control of AC motors has propelled the use of electric ...

Multiphase variable speed drives are nowadays regarded as serious contenders for various applications, due to the certain advantages that they possess when compared to threephase drives. On the other hand, the multilevel (predominantly three-level) voltage source inverter (VSI) has become an industrially accepted technology for medium-voltage three-phase drives. The logical next step is to inte...

Three-phase induction motors have been used in a wide range of industry applications. Using modern technology, the speed of induction motor can be easily controlled by variable frequency drives (VFDs). These drives use high speed power transistors with various switching techniques, mainly PWM schemes. For several decades, conventional control systems were applied to electric drives to control t...

The paper focuses on some aspects of control and estimation in electric drives with inverter output filters. The filters are used in some industrial drives with pulse width modulated (PWM) inverters. They smoothes the motor supply voltage and current so nearly sinusoidal shapes are obtained. The filters can also limit the bearing current and shaft voltages. Because of the voltage drop and phase...

Dielectric nonlinear response of (PbMg1/3Nb2/3O3)0.9(PbTiO3)0.1 (0.9PMN0.1PT) relaxor ceramics was investigated under different ac drive voltages. It was observed that: (i) the dielectric permittivity is independent on ac field amplitude at high temperatures; (ii) with increasing ac drive, the permittivity maximum increases, and the temperature of the maximum shifts to lower temperature; (iii) ...