Papers by Author: A. Baskys

Abstract: The course of microcontrollers oriented to practical skills that is lectured at the Electronics Faculty of Vilnius Gediminas Technical University is presented and discussed in this paper. This course is dedicated to the students of the Basic studies. The laboratory works and the course project, which are of high importance in obtaining the capability to develop microcontroller-based control systems, play a key role in this course. The Mid-range architecture family of PIC (Peripheral Interface Controller) microcontrollers developed and produced by the Microchip company was chosen as the basis for the studies. The structure of lectures, the description of specifics of laboratory works, the course project and the examination procedure are presented here as well. The answers of students indicate that the course has good appreciation. This course is evaluated positively by the institutions involved in the development of the microcontroller-based devices.

Abstract: The paper proposes an algorithm for control of processes based on variable-speed drives with low acceleration and deceleration rate of the motor, which determines the dynamics of the whole control system. The results of investigation of the controller based on the proposed algorithm are presented and discussed. The controller provides good transient performance of the control system response in case when the drives with different motor acceleration and deceleration rates are used.

Abstract: This paper presents investigation results of the influence of the supply voltage amplitude variation law on the efficiency of AC induction motor in variable-speed drive based on the frequency converter. It is demonstrated that the commonly employed linear and square voltage amplitude variation laws do not provide the highest efficiency of the AC induction motor. The corrected AC voltage amplitude variation dependences for different motor load torque, at which high efficiency of the motor supplied by the frequency converter is maintained, are proposed and discussed. Reported experimental study was performed on a special test bench.

Abstract: An asymmetric PI (aPI) controller based on a control algorithm, which is the modification of the PI control method, has been suggested. The principal characteristic feature of the aPI controller is that different values of proportional and integral constants are used at positive and at negative errors. Contrary to the classical PI controller, the proposed controller allows us to improve the positive disturbance rejection of control systems without sacrificing the unit step response dynamics. Results of the investigation of the concrete control systems based on the aPI controller are also presented. Using the dynamic system simulation program Simulink performed the investigation.

Abstract: A model of the AC induction motor, which allows us to analyze all operation modes of motor supplied by the frequency converter, has been developed. A simulation of the inverter of the frequency converter and the AC induction motor interaction on the basis of the developed motor model, using software MATLAB, was performed and a motor regenerative braking mode was investigated. The results of investigation are used for the development of fault protection of the inverter.