walnuts are one of the most important nut crops worldwide. the area under cultivation increases every year. in 2008, the food and agriculture organization reported exports of about $17.1 billion. the country of iran is the 4th largest producer of walnuts in the world. stages from production to consumption are very important, because the condition and quality of the shelled nutmeats affects the ...

In the speed sensorless vector control system, the amended method of estimating the rotor speed about model reference adaptive system (MRAS) based on radial basis function neural network (RBFN) for PMSM sensorless vector control system was presented. Based on the PI regulator, the radial basis function neural network which is more prominent learning efficiency and performance is combined with M...

1. A description is given of the construction details and operation characteristics of an improved type of air-driven ultracentrifuge operating in vacuum and suitable for the determination of sedimentation constants of protein molecules. 2. The rotor of the centrifuge is made of a forged aluminum alloy; it is oval in shape, measures 185 mm. at its greatest diameter, and weighs 3,430 gm. It carr...

Model reference adaptive system (MRAS) based techniques are one of the best methods to estimate the rotor speed. Speed and torque control of an induction motor is usually attained by application of a speed or position sensor. However, these require the additional mounting space, reduce the reliability and increase the cost of the motor. The recent trend in field oriented control (FOC) is toward...

In this paper, a sensorless permanent magnet synchronous motor (PMSM) drive was presented based on calculating the back EMF using reference stator voltages, which are output of d-axis current controller, includes information about rotor position. Sensorless control estimates position necessary for vector without sensor or encoder. This can provide effects such as increased system reliability an...

The aim of this paper is to implement a sensorless indirect rotor-flux-oriented control (IRFOC) of induction motor (IM) drives. Indeed, the proposed method for speed estimation is based on Luenberger state observer (LSO). The adaptive rotor speed is actually derived from Lyapunov stability theory by using measured and estimated stator currents and estimated rotor flux. The proposed control sche...

This paper deals with an improved use of phasor measurements. In particular, the paper focuses on the development of a technique for estimation of generator rotor angle and speed, based on phasor measurement units, for transient stability assessment and control in real-time. Two multilayered feed-forward artificial neural networks are used for this purpose. One for the estimation of rotor angle...

Two different nonlinear dynamic control algorithms are presented for synchronous motors with damping windings: (i) an adaptive speed-sensorless controller for rotor position tracking in the presence of unknown constant load torque, on the basis of rotor angle, stator and field windings currents measurements; (ii) an adaptive control law for rotor speed tracking in the presence of uncertain cons...

We report on the design, construction, and testing of a high-speed rotor intended for use in hypervelocity microparticle impact studies. The is based four-wing design to provide rotational stability includes flat “paddle” surfaces ∼0.5 cm2 at tips each wing. profile wing minimizes variation tensile forces any given speed. was machined using titanium (grade 5) operated high vacuum magnetically l...