Modern utility-scale wind turbines are typically controlled using yaw, generator torque, and blade pitch actuation (Pao and Johnson, 2011). The yaw motor is used to align the rotor with the wind direction for the purpose of maximizing power capture. Generator torque is controlled during below-rated (region 2) operation to maximize power capture by maintaining the optimal tip speed ratio. In abo...

in conventional direct torque control (dtc), the stator flux is usually kept constant by controlling the x-axis component of the stator voltage in the stator flux reference frame. the torque is then controlled by the y-axis component of stator voltage. in this scenario, the stator current does not exceed its permissible value. however, in the so-called optimal efficiency mode, the induction mot...

the suppression of the regenerative chatter phenomenon in turning process via the variation of the frequency and amplitude of the spindle motor excitation is carried out in this research. a programmable inverter is employed for variable periodic excitation of the spindle motor. a set of turning experiments is designed and performed on a number of conical work pieces both in constant spindle spe...

This paper describes the calculation of torqueina brushless permanent-magnet line-start a.c. motor by means of the ~~UX-MMF diagram in combination with the finite-element method. Results are compared with measured ~~UX-MMF diagrams, with shaft torque measurements, and with torque calculated using the classical phasor diagram.

the efficiency of induction motors decreases at light loads. efficiency optimizer control systemsadjust the motor flux value to achieve the best efficiency in a wide range of load variations. reduced fluxoperation has some other benefits such as power factor improvement and torque ripple reduction. the latter isan important issue in a direct torque controlled induction motor drive. in this pape...

sensorless speed torque control of induction machines has been widely used in many industrial applications. the simple method of direct vector control can provide tacholess control as well as more complex approaches. in this method, the motor flux can be obtained by measuring voltage and current and integrating motor back electromotive force. the only required motor parameter is stator resistan...

The direct torque control (DTC) speed control scheme of an induction motor surpasses the vector control in the sense that it controls the torque directly and does not use transformations and current modulator. In the traditional direct torque control (DTC) of induction motor, the low order harmonic component of stator current is very large when the motor is running at low speed. It leads to hig...

torque, speed, and power as mechanical variables are associated with the functional performance of any rotating machinery. the real-time performance and the efficiency of a machine can be determined with on-line measurement of these parameters. in this investigation a rotary torque meter (transducer) was constructed from strain gauge sensors for measuring the torque of rotating shafts. the syst...

Simple power electronic drive circuit and fault tolerance of converter are specific advantages of SRM drives, but excessive torque ripple has limited its application. This paper presents a novel method of controlling the motor currents to minimize the torque ripple, using a neuro-fuzzy compensator. In the proposed control concept, a compensating signal is added to the output of a classical PI c...

Nowadays, piezoelectric materials have wide applications in various industries. Therefore, investigation of these materials and their applications has a special importance. In this paper first, the natural frequencies of a traveling-wave piezoelectric motor are achieved, using finite elements simulations. Then, applying an alternative electrical voltage to the piezoelectric ring, a traveling wa...