A controller of PMSM for elctrical bicycle with hall effect sensors
In this paper, rotor position and speed estimation method using hall-effect sensors for low-cost vector controller design is presented for Permanent Magnet Synchronous Motor (PMSM). Sensorless control and self-learning implementation was also realized based on theoretical analysis. Experimental results verified the feasibility of the proposed control strategies.
Intelligent control of high-speed sensorless brushless DC motor for intelligent automobiles
For the last decade, the need for electric driven vehicle has risen rapidly due to the global warming problem. A high efficient motor need to be developed to replace traditional engine. In this paper, the authors present a fuzzy logic controller (FLC) for sensorless brushless dc (BLDC) motor. The proposed FLC is based on the terminal voltage measurement as the sensorless method for BLDC motor control. There are two modules designed in the speed control of BLDC motor, i.e. command and regulating modules. Command module is to find and issue commutation period and PWM duty cycle to the BLDC motor for desired speed. The regulating module is designed by applying a FLC with sensorless technology and is used to regulate the speed of BLDC motor under various disturbances, such as loading effect. Two resistances are adopted to detect the zero-crossing point (ZCP) of back-EMF signal on the unexcited phase instead of using the expensive Hall sensors. The regulating module can regulate accurately and quickly the PWM duty cycle by fuzzy reasoning which makes the BLDC motor rotate smoothly at desired rotation speed even there exists an external disturbance. In order to reduce the computational load of real-time FLC for the microcontroller C8051F330, we can perform the FLC computation off-line to cover nearly all cases. These data will be recorded and organized as a Look-Up Table (LUT). This paper shows that a regulating module designed by FLC is better than a none regulation module or a regulating module with a P controller.
Mechanical behaviour and durability of high volume fly ash cementitious composites
The purpose of this research is to separate different morphological particles of ASTM class F fly ash, and study their effect on mechanical behaviour and durability of high volume cementitious mixtures. In this research wet separation of raw fly ash is carried out, which resulted in three layers of different morphological particles. The first layer of particles float, comprise of about 1-5% of fly ash, is identified as cenospheres or hollow spheres. The second layer of particles is measured to be 55-60% of raw fly ash and consisting of porous spherical and rounded particles rich in Si and Al. The third layer particles is measured to be about 35-40% of raw fly ash. High volume fly ash cementitious composites containing second or third layer particles are tested under compression and bending, highlighting a higher strength and ductility in comparison to cementitious ones containing raw fly ash particles. KEYWORDS. Cementitious matrix; Raw fly ash; Second layer particles; Third layer particles.