This paper presents results of a comparative study of two possible hybrid filter topologies, comprised of a passive and active stage, which can be implemented in any general dc supply distribution system. The active stage is incorporated into the passive part in order to: 1) improve its insufficient attenuation in the low-frequency range and 2) source or sink any surplus energy flow between the dc source and load in case of low-frequency current dynamics. In the low-frequency range nearly for 15 dB higher attenuation compared to the passive filter is achieved.
COBISS.SI-ID: 7554388
This paper describes an adjustable speed drive system for driving an induction motor beyond its nominal speed, even in the presence of input voltage sags. The control of the induction motor is carried out with the field oriented control coupled with the field weakening regime of the induction motor. The experimental setup is based on a prototype with a DSP control system to verify the operation of the proposed system.
COBISS.SI-ID: 8150356
Breaking of rotor bars in an induction motor is one of the most common damages industry has to cope with. For its detection at an early stage, many approaches have been developed. The common denominator of all is relatively complicated algorithms. In this paper, we propose a method that would warn in a simple manner of a trend of breaking of increasing number of bars, using an existing hardware. The method relays on a measurement of the stator voltage. After its filtering, a deviation from an average voltage of a healthy rotor becomes an indication of gravity of a fault.
COBISS.SI-ID: 7819604
Although the existing current sensing technique on MOSFET RDS(on) is lossless, its inaccuracy, which is mainly the consequence of the temperature dependence of RDS(on), is the reason why it is not utilized more frequently. In order to considerably improve the accuracy, we propose to thermally couple the power MOSFET and the sensing MOSFET. We present two methods for minimization of the current ratio temperature dependence, i.e. optimization of resistance for the sensing resistor variant and optimization of the thermal contact with the virtual ground sensing circuit.
COBISS.SI-ID: 7632980
The paper outlines a case study on optimal control of a brushless direct-current (BLDC) motor as a part of an Integrated Starter-Generator and torque Booster (ISGtB) application in a hybrid propulsion system. Two approaches for the optimization of the torque characteristics are discussed, the flux-weakening method and a modification of transistor conduction angle. Results fully confirm improvements in the starting procedure of the hybrid propulsion system attained by the proposed control algorithm of the BLDC motor.
COBISS.SI-ID: 7780692