TY  - CHAP
A1  - Himmelstoss, Felix
A1  - Windisch, Michael
T1  - A capacitor-free driving stage for light emitting diodes
T2  - 21th International Conference on Renewable Energies and Power Quality (ICREPQ’23) Madrid (Spain), 24th to 26th May 2023
N2  - Electrolytic capacitors have the disadvantage of
pronounced aging. Non-electrolytic capacitors are therefore used
in applications where long-life is important. In this paper we
present a driving stage for LEDs without any capacitive
elements. The basic topology is a Buck converter with one coil,
one active, and one passive switch. Instead of the output
capacitor, series connections of one or more LEDs and an active
switch are connected. An additional diode is connected between
the output and the input to achieve a current path, when all LED-
paths are off. A nonlinear hysteresis controller is used to achieve
a robust control. A system with three switchable LED-strings is
analyzed. Design hints are given and the function is proved with
the help of LTSpice simulations. The system can be used for
lighting purposes with the possibility to change the chrominance.
The potentiality to transmit data is also treated.
KW  - DC-to-DC converter
KW  - stray inductance
KW  - recuperation
KW  - active snubber
Y1  - 
U6  - http://dx.doi.org/10.24084/repqj21.278
VL  - Vol. 21
SP  - 220
EP  - 225
ER  - 
TY  - CHAP
A1  - Himmelstoss, Felix
A1  - Windisch, Michael
T1  - Tapped inductor Boost with exploitation of the stray energy
T2  - Proceedings of 2022 IEEE 20th International Power Electronics and Motion Control Conference (PEMC 2022), Brasov, Rumania, Sep. 25-29
N2  - Tapped inductor DC-to-DC converters are interesting circuits, the winding ratio of the two windings mounted on the same core change the voltage transformation ratio compared to the untapped inductor. The tapped inductor converters are especially useful, when high or low voltage transformation ratios have to be realized. The disadvantage of this concept is that the coupling between the two windings is not total and can be described by the stray or leakage inductance. This stray inductance leads to a high overvoltage at the active switch, and therefore also across other elements of the converter. After a short summery of the ideal tapped Boost converter, the design of an RCD snubber which limits the overvoltage is explained. To improve the efficiency of the converter two active snubber networks are treated, which feed the energy stored in the snubber capacitor into the input source or into the output circuit. Simulations are used to prove these considerations.
KW  - DC/DC converter
KW  - stray inductance
KW  - recuperation
KW  - active snubber
Y1  - 
U6  - http://dx.doi.org/10.1109/PEMC51159.2022.9962849
SP  - 75
EP  - 80
ER  -