Adjustable Speed System Research Articles

Cylindrical Magnetorheological Fluid Variable Transmission Controlled by Shape-Memory Alloy

Centrifugal fan is an important component of a ventilation system in a nuclear power plant. In this paper, we proposed a magnetorheological speed-adjustment system controlled by shape-memory alloy for centrifugal fan. A theoretical analysis of the effect of the applied magnetic field on the viscoplastic flow between two cylinders in the speed-adjustment system is presented. The expressions for the velocity in viscoplastic flow and the torque transmitted by MR fluids are derived. A sliding mode SMA switch is proposed to modify the magnetic field acting on working gap under thermal effect. The results indicate that with the increases of applied magnetic field, the torque transmitted by MR fluid goes up rapidly.

The Simulation Research of Rotor Flux Model in Asynchronous Motor Control

The speed-adjustable system of asynchronous motor has been widely used in industrial production. in motor control, magnetic control is a key problem, but in order to realize the control of motor, magnetic field must be tested. The testing methods about rotor flux according to the rotor field-oriented control of motor are discussed in this paper. The paper describes the present two rotor flux calculation models: Voltage model and Current model. It concretely analyzes mathematical expressions of these two models in different coordinates, and realizes the matlab simulation of two kinds of model, the simulation results are compared by observations of the magnetic chain calculation results.

The Design and Realization of Digital Controlled Frequency-Variable Speed-Adjustable System Based on DSP and SVPWM

The paper introduces voltage space vector pulse wide modulation (SVPWM) arithmetic and the field oriented control (FOC), develops a suit of Digital Controlled frequency-variable speed-adjustable system based on digital signal processor (DSP) TMS320LF2407 of TI company For motor control, and research and analyze design parts of the system, presents the instantiation application result. The experimental results indicate: the laboratorial setting has a simpler hardware construction, less output current harmonics distortion, higher control precision and stronger real-time sigal processing.

Research of the Welding Wire Sending System Based on Fuzzy Adaptive-Adjusting PID Control

This article employs single closed loop of voltage negative feedback circle to explore the welding wire sending system of arc welder, as the system of this style has the feature of rough sending and poor dynamic behavior. A double closed loop PWM digit speed adjustment system is proposed based on fussy adaptive-adjusting PID control algorithm. The experiment result indicates that this control system not only has a sound dynamic behavior and static behavior but also has a strong self-adapting behavior, and mostly eliminates the arc flutter made by the rough welding wire sending system.

Hardware-in-the-Loop Simulation of Speed-Adjusting System for DC Motor Based on dSPACE

Based on dSPACE real-time simulation system and LabVIEW measuring system, semi-physical simulation platform of DC motor speed-adjusting system was established. Fuzzy PID algorithm was designed based on analyzing fuzzy control and PID control for speed-adjusting system. The simulation results show that compared to standard PID algorithm, fuzzy PID algorithm improves the performance of speed-adjusting system for DC motor. On this basis, the speed-adjusting system was developed based on ATmega128 single-chip and original algorithm. Compared with simulation speed-adjusting system, there is no obvious difference on response characteristics.

Sinking-hoists synchronous balance control system in vertical shaft

In order to solve the problems existing in traditional shaft sinking-hoists, the variable-frequency adjustable-speed system was designed for the sinking-hoists firstly. Then, taking four platform sinking-hoists as the research object, we studied strategy of synchronous controls of the sinking-hoists based on PID and model-reference adaptive control, simulated the performances of the synchronous strategy, and performed the field test. The results show that, after the reconstruction of controls parameters, the ability of anti-disturbance of the controls system have been enhanced and the motor speeds and sinking depths of the sinking-hoists have a great synchronous effect, greatly improved the predictability of the system.

The structure and adjusting speed characteristics of new type of doubly‐fed brushless machine with ALA rotor

AbstractThis paper introduces the structure and operation modes of a doubly‐fed brushless machine (DFBM) with axially laminated anisotropy (ALA) rotor. The air gap magnetic field of the DFBM is analysed by means of the field modulation theory. The coupling parameter between the stator main and auxiliary winding is tested and discussed. The adjusting speed performance of the DFBM is also presented in this paper. It is indicated that the DFBM adjustable speed system needs only a much smaller power inverter in comparison with the adjustable speed system using a conventional AC motor. Copyright © 2006 John Wiley & Sons, Ltd.

Power Factor Modified Scr Dc Speed Adjusting System by Single-Chip Microcomputer 8098

This paper introduced a power factor modified SCR DC speed-adjusting system controlled by 8098. By using three-phase four-wire bridge structure, the main circuit can improve power factor & output resolution, decrease current harmonic wave and decrease system cost.

Adjustable speed and vibration-free hydraulic system for Langmuir–Blodgett films deposition

Conventional apparatus for the dipping and raising of slides usually uses an electric motor with the slides fixed in a rigid holder. Most of the devices create a great deal of vibrations and this produces a nonuniform film deposition. We have used a new apparatus, which does not produce any vibrations of the slide, to build up Langmuir–Blodgett films. To move the slide, we employ a column of water and use the siphon principle, with speeds that can be varied between 3.0 and 120.0 mm min−1. An electronic circuit controls the automatic dipping and raising of the slide. A relay switches the solenoid valve to move the piston in the opposite direction. A machined Teflon trough and antivibration mount are used for the monolayer preparation. With this method, the deposition ratio usually obtained for the cadmium arachidate and chlorophyll a is 1.00±0.05. The absorption spectrum of multilayers of chlorophyll a give a linear relation between the absorbance at 680 nm and the number of layers up to 10. The nonlinear relation for the number of layers higher than 10 is explained by the presence of aggregates.