U ovom radu prikazana primena algoritma proširenog
Kalmanovog filtera (Extended Kalman Filter - EKF) u
estimaciji stanja asinhronog motora, sa mogućnošću
estimacije električne brzine obrtanja i mehaničkog momenta
opterećenja na vratilu. Radom je obuhvaćen postupak sinteze
osnovnih jednačina EKF algoritma i prikazani su rezultati
testiranja za slučaj direktnog puštanja u rad asinhronog
motora u neoptrećenom i opterećenom stanju. U radu je
uočena ostljivost algoritma na nagle promene momenta
opterećenja pa je predloženo uvođenje posebne funkcije po
kojoj se menja koeficijent matrice kovarijansi Q koji
definiše poverenje EKF algoritma u procenu mehaničkog
momenta opterećenja. Rezultati testiranja pokazuju da se
na ovaj način postižu dobri rezultati u estimaciji
električne brzine obrtanja i mehaničkog momenta opterećenja
na vratilu motora.

Cilj ovog rada je da se prikaže proračun karakteristika
strujnog mernog transformatora (ST) sa torusnim jezgrom od
feromagnetskog lima. Proračun uzima u obzir magnetski
histerezis jezgra primenom metoda interpolacije harmonika
na jačinu magnetskog polja i magnetsku indukciju. Na osnovu
unapred zadatih karakteristika ST, parametara jezgra i
poznate familije histerezisnih petlji vrši se proračun
greške prenosnog odnosa i fazne greške za različite
vrednosti primarne struje. U radu su prikazane i
analizirane vrednosti proračunatih grešaka u opsegu od 5%
do 120% naznačene primarne struje ST za 500 A. Dodatno,
analizirana je promena grešaka kada se isto jezgro koristi
za izradu ST sa naznačenom primarnom strujom u opsegu od
200 A do 1000 A.

Gallium-Nitride (GaN) transistors are increasingly
used in the design of low voltage high power density power
converters. To use this technology to its full potential it
is necessary
to understand and minimize power losses. In this paper, two
models for estimating power losses in GaN transistors are
analysed
and compared against circuit-level simulations. The total
losses are
separated into individual components, which are evaluated
independently, since some loss mechanisms are inherently
more
difficult to estimate. The analysis is performed on several
commercially available 100 V rated GaN transistors and their
performance is assessed across a wide range of operating
conditions. Reverse conduction losses are explained in
detail, as
they can be comparable to other loss components in GaN
transistors. Final results provide comparison between the
two
estimation models and guidelines for optimal device
selection
depending on the application.

This paper analyzes the impact of inductor coupling on
total magnetic-component losses in a SEPIC converter. Since
the benefits of magnetic coupling depend on the specific
converter parameters and operating conditions, a numerical
evaluation is required in order to quantify its actual
impact on loss reduction. The proposed approach combines
coupled inductor modelling, analytical inductance
calculation, core and copper loss calculations, and a sweep
of Ferroxcube E-core geometries. Additionally, Ansys
Maxwell simulations are used to confirm the trends observed
in the obtained analytical results. For the analyzed
volume-matched cases, the coupled inductor solution
achieved lower total loss with mean total loss reduction
for all analyzed sets close to 24%. It was also shown that
the main benefit of coupling comes from copper loss
reduction, with the average copper volume reduced by almost
17% in the considered application. These results show that
properly designed magnetic coupled circuits can represent
an effective approach for improving efficiency by reducing
magnetic losses and improving copper utilization in SEPIC
converters.

—The objective of this paper is to present a digital
signal processor-based control system for a SEPIC operating
in discontinuous conduction mode. By deriving an analytical
full-order model of the converter under current programmed
control, the application of an H∞ loop-shaping design
procedure
is facilitated. The resulting output voltage controller
robustly
compensates for the accurately modelled converter dynamics
that
appear within the desired closed-loop bandwidth.
Furthermore,
practical implementation guidelines are provided for a Texas
Instruments digital signal processor, leveraging its
on-chip comparators
and digital-to-analog converter modules with integrated
compensating ramp generation. Hardware-in-the-loop
simulations
are performed utilizing a Typhoon HIL 404 real-time
simulator to
validate the control system design for powering
Electromagnetic
Vibratory Actuators.

High-inertia electrical drives generate substantial amounts
of excess energy during the braking regime. This energy
must be managed by the power converters either by
dissipation or by returning generated energy back to the
power source. The braking chopper and active rectifier
DC-link voltage control methods are compared in terms of
DC-link voltage overshoot during the motor braking regime
for an electrical drive system with a wide range of
inertia. This paper investigates the performance of the
topologies that illustrate these two principles. Practical
implementation advantages and drawbacks for both methods
are listed and discussed.

A test bench is developed for experimental verification of
a manufactured RPMFS (Rotor Permanent Magnet Flux
Switching) motor prototype, previously designed by the
authors. In the test bench, the RPMFS motor prototype is
mechanically coupled to an induction machine via a torque
sensor. Both machines are supplied by two three-phase
voltage source inverters (VSIs) with shared DC buses and a
braking resistor, powered from the mains supply by a
single-phase diode rectifier. Real-time speed and torque
control of the tested prototype is implemented using the
TMS320F28335 digital signal processor (DSP), connected to
all sensors and one of the VSIs by an interface PCB
designed by the authors. The DSP is connected to a PC
through USB/JTAG interface, which enables recording and
monitoring of waveforms and responses of all measured and
controlled quantities during experiments. The paper
provides a detailed description of the developed test bench
with schematics of measuring and control circuits and
explanations of the DSP program, which is implemented using
the C2000TM Microcontroller Blockset library in MATLAB®
Simulink® environment. Results of conducted experiments
confirm the applicability of the test bench and the
validity of models used to design the RPMFS prototype.

This paper summarises the method of calculating the
inductance of all windings in a synchronous machine using
the concept of the winding function. The obtained results
are then compared with those obtained using the classical
method, i.e. by employing analytical expressions where such
expressions exist. Conversely, the actual winding with
parallel-connected groups is modelled by a fictitious
winding with series-connected turns. The application of the
winding function concept allows for the accounting for all
higher harmonics in the MMF wave, in contrast to classical
calculations that are based on the fundamental harmonic
only. The presented method of calculation is general and
can be applied to both conventional synchronous machines
and to reluctance machines with or without permanent
magnets in their structure, with previous knowledge of the
air-gap permeance function.

This paper investigates rotor position estimation in
shaft-sensorless permanent magnet synchronous motor (PMSM)
drives with emphasis on the impact of system delays at high
speeds. Existing voltage-based rotor position estimators
often neglect the cumulative delays from sampling,
computation, PWM, and filtering, which leads to degraded
accuracy. The hypothesis is that proper delay
handling—either through explicit compensation can
significantly improve estimation performance. The aim is to
experimentally compare estimation methods based on
reference voltages, delay-compensated reference voltages,
and measured motor voltages, and to evaluate PLL-based
position estimation using a flux estimator under different
delay configurations. Results show that uncompensated
estimation produces significant position error, while delay
compensation greatly improves accuracy. Estimation based on
measured voltages achieves comparable performance by
inherently including delay effects. Additionally, PLL
performance is optimal when delay compensation matches the
actual system delay. These findings highlight the
importance of delay-aware design in sensor-less PMSM
control.