Browsing by Author "Ghosh, Dr. Bashudeb Chandra"

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Design and Analysis of Field Oriented Control of Permanent Magnet Brushless DC Motor
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2017-05) Islam, Md. Ashraful; Ghosh, Dr. Bashudeb Chandra
This research project is about Field Oriented Control strategies for Permanent Magnet Brushless DC (PMBLDC) Motor. In PMBLDC Motor for Field Oriented Control direct axis reference current Id ref is considered zero, therefore forces the current space vector in the quadrature direction. Since only the quadrature axis current produces useful torque, this maximizes the torque efficiency of the system. Three PMBLDC Motor Control systems are designed, namely (1) Sinusoidal Current Regulated Pulse Width Modulation (CRPWM) Control, (2) Square Wave Current Regulated Pulse Width Modulation Control and (3) Voltage Regulated Space Vector Pulse Width Modulation Control. A state space model consisting three phase currents, three phase voltages, speed and position is developed. For testing, C++ simulation programs are designed for these three control strategies. The performance of the proposed control methods are studied for starting condition, load torque changes, speed variation, stator resistance changes and initial rotor angle mismatch condition. We have observed that Field Orientation Control methods have good performance and speed response. But speed response in Space Vector Pulse Width Modulation Control is better. Overall performance of all three control methods are proved satisfactory for speed control. A simple experiment is also done in the laboratory with a prototype design by using customized software in an electronic control board with integrated inverter. There is a built in position sensor embedded on the motor. The system was run in open loop and found to work satisfactorily.
Parameter Adaptive Vector Controller for CSI-fed Induction Motor Drive and Generalized Approaches for Simulation of CSI-IM System
(Indian Institute of Technology (IIT), Kharagpur, India., 1992-07) Ghosh, Dr. Bashudeb Chandra; Bhadra, Prof. S. N.
The main subject matter of this dissertation is to develop parameter adaptive rotor flux oriented current fed induction motor drive systems for controlled speed operation. The parameter adaptive approaches do not require special test signals and softwares in a big way. Three easy-to-implement schemes are suggested. One scheme is based on airgap power estimation method and takes into account of the non-linear magnetic state while tracking the actual rotor resistance. The other two methods constitute model reference adaptive controllers. They are based on the inverter input voltage and torque producing component of the stator current. The effectiveness of these methods is examined by extensive simulation and experimentation with two laboratory type induction machines. The experimental set up makes use of two microcomputers (i-8006 with i-6007) and a PC/AT with Burr Brown's PCI system having multi-channel 12 bit data acquisition modules for implementing the control algorithms. Prior to the description of parameter corrective algorithms, a control system suitable for a CSI-fed induction motor under rotor flux orientation is designed and tested by suitable simulation model. Then the influence of rotor resistance variation in the presence of magnetizing flux saturation has been extensively investigated. A two-parameter saturation model (two-term quintic non-linearity) is used in all these studies. It is further shown how the machine performances under field oriented condition are affected inclusion of saturation characteristics. Analytic expressions as well as digital simulation procedures are presented to study the performance of the drive system. Robustness of the drive system has been studied applying the concept of Kharitonov's theorem and then justified from the simulation results of the system for both parametric and torque disturbances. 'Bond Graph' and 'Nodal method' provide an organised way to write equations for a dynamic system. Tedious way of writing equations and their arrangement and re-arrangement for framing state equations can be avoided in the proposed simulation techniques. Simulation studies based on systematic modelling and framing of the system equations using the above two methods for the operation of a speed controlled CSI-IM system under normal and abnormal conditions have also been provided.