There are several sources for pressure oscillations in solid propellant rocket motors. Oscillatory flow field is one of them. Free shear layers in motor flow field cause vortex shedding. End edges of propellant grains and baffle edge in two-segmented motors are samples of such zones. These vortices move from their forming points and strike the field walls. The kinetic energy of vortices change ...

There are several sources for pressure oscillations in solid propellant rocket motors. Oscillatory flow field is one of them. Free shear layers in motor flow field cause vortex shedding. End edges of propellant grains and baffle edge in two-segmented motors are samples of such zones. These vortices move from their forming points and strike the field walls. The kinetic energy of vortices change ...

An adaptive online flux-linkage estimation method for the sensorless control of switched reluctance motor (SRM) drive is presented in this paper. Sensorless operation is achieved through a binary observer based algorithm. In order to avoid using the look up tables of motor characteristics, which makes the system, depends on motor parameters, an adaptive identification algorithm is used to estim...

A new squirrel-cage rotor structure induction motor (IM) that has a auxiliary permanent magnet (PM) rotor and improved cage-rotor structure is presented to enhance the inherent power factor of the IM, and a prototype motor is fabricated by modifying the rotor of a conventional three-phase four-pole squirrel-cage induction motor. The flux linkage, flux distribution, power factor, core loss and e...

In the present paper a simple sensorless spccd estimation scheme is presented , where the speed information is obtained from the motor phase current ripple. The scheme measures the stator current phasor deviation direction to determine the back emf vector position during inverter zero vector switching states. This measurcment of rotor flux position is done indirectly by computing the motor back...

An electric bus system has been operating in the downtown area of Chattanooga, Tennessee for more than four years. The buses use traditional hard-switched IGBT inverters driving special induction motors with a speed sensor (tachometer) and two embedded fluxsensing windings to provide rotor speed and flux information to the motor controller for implementation of high performance field oriented c...

_ Speed control of permanent magnet synchronous motor (PMSM) using Direct Torque Control has rapid response and good static and dynamic performance but less accurate since current, torque and flux linkage wave forms contain big ripples. To overcome these disadvantages stator flux linkage and rotor speed are estimated using Extended Kalman Filter. Therefore, sensorless speed control of surface p...

In this paper, an improved rotor structure with cross-shaped flux-barriers was proposed to improve the torque output capacity and reduce ripple of synchronous reluctance motor (SynRM). Firstly, flux-barriers, which can be described by two main parameters, is presented. Second, qualitatively analyzed using magnetic equivalent circuit (MEC), then effects parameters on distribution air-gap flux de...

This paper presents the design, analysis, and prototyping of a novel axial-flux permanent-magnet (AFPM) motor capable of auto-starting. The preliminary design is a slot-less double-sided solid-rotor line-start AFPM motor with 4 poles for high torque density and stable rotation. One spaced raised ring was added to the inner radii of the rotor disc for smooth line-start motor. The design allows t...

This paper present a new advanced control algorithm based on continuous minimization of predicted tracking errors, to achieve torque, rotor speed and rotor flux amplitude tracking objectives. This algorithm called a new Adaptive Nonlinear Predictive Control to induction motor drive uses a combination of the adaptive observer for rotor flux and Cascaded Nonlinear Predictive Control technique. Th...