The development of ARM-based portable and adaptable power supplyTomislav Brlek
, 2019, magistrsko delo
Opis: This master’s thesis describes a development of a portable and adjustable power supply. The first part of the thesis introduces us to the working principle of power supplies in general. Next, we present a functional design of a portable and adjustable power supply and a list of its required functionalities. Chapter “switched-mode power supplies” introduces us to the theoretical basics of the said power supplies, while chapter “linear regulators” introduces us to different types of linear regulators and tells us more about how they work. Everything regarding which microcontroller was used and why it was used is described in the “ARM microcontroller” chapter. Besides microcontrollers, it also talks about which integrated development environment is used and how the microcontroller is programmed. A full and detailed description of each part of the analog circuitry can be found in the chapter “describing the development of the portable and adjustable power supply”. Lastly, the user interface is described in detail.
Ključne besede: portable power supply, ARM processor, variable laboratory bench power supply, LCD touchscreen, energy efficient, lithium battery, battery charger, voltage control
Objavljeno: 13.11.2019; Ogledov: 395; Prenosov: 67
Celotno besedilo (3,85 MB)
Validation test plan for relays in avtomotive industryUrban Cotič
, 2017, magistrsko delo
Opis: The master’s thesis discusses different approaches how to assure the quality and reliability of high voltage contactors in automotive industry. In the beginning, the history of the development is described, followed by basic knowledge about materials and magnetic theory used in relays. The main part of the thesis is tests defying to qualify the relays for usage in automotive industry. There are different tests, divided in different groups. Second important part is reliability prediction according to standards used in this area of business. Reliability prediction and calculation of failure rate on different contactors are described in last chapters. Calculation also included influence of different factors on life span of the parts. In conclusion, the results are commented and proposal for development is given based on results of the research.
Ključne besede: Automotive industry, high voltage contactors, testing, reliability, failure rate
Objavljeno: 07.02.2018; Ogledov: 820; Prenosov: 76
Celotno besedilo (1,89 MB)
SOFT SWITCHING FOR IMPROVING THE EFFICIENCY AND POWER DENSITY OF A SINGLE-PHASE CONVERTER WITH POWER FACTOR CORRECTIONTine Konjedic
, 2015, doktorska disertacija
Opis: This thesis investigates the possibilities for increasing the power conversion efficiency and power density of a single-phase single-stage AC-DC converter with power factor correction capability. Initially, the limitations are investigated for simultaneous increase of power density and efficiency in hard switched bidirectional converters. The switching frequency dependent turn-on losses of the transistors have been identified as the main limiting factor. In order to avoid the increase in total power losses with increasing the switching frequency, a control approach is proposed for achieving zero voltage switching transitions within the entire operating range of a bidirectional converter that utilizes power transistors in a bridge structure. This approach is based on operation in the discontinuous conduction mode with a variable switching frequency. Operation in the discontinuous conduction mode ensures the necessary reversed current that naturally discharges the parasitic output capacitance of the transistor and thus allows this transistor to be turned on at zero voltage. On the other hand, the varying switching frequency ensures that the converter operates close to the zero voltage switching boundary, which is defined as the minimum required current ripple at which zero voltage switching can be maintained. Operation with the minimum required current ripple is desirable as it generates the lowest magnetic core losses and conduction losses within the power circuit.
The performance and effectiveness of the investigated approach were initially verified in a bidirectional DC-DC converter. A reliable zero voltage switching was confirmed over the entire operating range of a bidirectional DC-DC converter, as well as the absence of the reverse recovery effect and the unwanted turn-on of the synchronous transistor. In order to justify its usage and demonstrate its superior performance, the proposed zero voltage switching technique was compared with a conventional continuous conduction mode operation which is characterized by hard switching commutations. After successful verification and implementation in a bidirectional DC-DC converter, the investigated zero voltage switching approach was adapted for usage in an interleaved DC-AC converter with power factor correction capability. Comprehensive analysis of the converter's operation in discontinuous conduction mode with a variable switching frequency was performed in order to derive its power loss model. The latter facilitated the design process of the converter's power circuit. A systematic approach for selecting the converter's power components has been used while targeting for an extremely high power conversion efficiency over a wide operating range and a low volume design of the converter.
The final result of the investigations performed within the scope of this thesis is the interleaved AC-DC converter with power factor correction capability. Utilization of interleaving allows for increasing the converter's power processing capability, reduces the conducted differential mode noise and shrinks the range within which the switching frequency has to vary. The proposed zero voltage switching control approach was entirely implemented within a digital signal controller and does not require any additional components within the converter's circuit. The experimental results have confirmed highly efficient operation over a wide range of operating powers. A peak efficiency of 98.4 % has been achieved at the output power of 1100 W, while the efficiency is maintained above 97 % over the entire range of output powers between 200 W and 3050 W.
Ključne besede: zero-voltage switching, power factor correction, variable switching frequency, discontinuous conduction mode, reverse recovery, unwanted turn-on, bidirectional DC-DC converter, bidirectional AC-DC converter, control of switching power converters
Objavljeno: 13.10.2015; Ogledov: 1456; Prenosov: 164
Celotno besedilo (23,37 MB)
Operation impact of the ICEM power testing laboratory on the Slovenian power networkMarjan Stegne
, Jože Pihler
, Jože Voršič
, 2007, izvirni znanstveni članek
Ključne besede: močnostni laboratoriji, močnostna preskušanja, preskusni tokovi, padci napetosti, simulacije, elektroenergetsko omrežje, high-power laboratory, power testing, test current, voltage drop, simulation, power system
Objavljeno: 10.07.2015; Ogledov: 1145; Prenosov: 19
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