Resonant Behaviour of Pulse Generators for the Efficient Drive of Optical Radiation Sources Based on Dielectric Barrier Discharges

Dielectric barrier discharge (DBD) excimer lamps emit vacuum-UV optical radiation. This work presents novel methods for efficiently operating DBDs with short, high-voltage pulses. Transformer-less systems utilising SiC power semiconductor switches are presented. Pulse frequencies of up to 3.1 MHz and peak inverter efficiencies of 92 % were achieved. The work encloses both mathematical backgrounds of pulsed resonant circuits and practical implementation of low-inductive power stages

Hard-switched switched capacitor converter design

Switched capacitor (SC) converters are becoming quite popular for use in DC-DC power conversion. The concept of equivalent resistance in SC converters is frequently used to determine the conduction losses due to the load current. A variety of methodologies have been presented in the literature to predict the equivalent resistance in hard-switched SC converters. However, a majority of the methods described are difficult to apply to general SC converter topologies. Additionally, previous works have not considered all nonidealities in their analysis, such as switching losses or stray inductances. This work presents a generalized and easy to use model to determine the equivalent resistance of any high-order SC converter. The presented concepts are combined to derive a complete loss model for SC converters. The challenges of implementing output voltage regulation are addressed as well. A current-fed SC topology is presented in this work that overcomes the problems associated with voltage regulation. The new topology opens up a variety of additional operating modes, such as power sharing. These additional operating modes are explored as well. The presented concepts are verified using digital simulation tools and prototype converters. --Abstract, page iii

Design of High Power Converter with SiC MOSFETs

Tato diplomová práce se zabývá návrhem výkonového měniče založeného na topologii typu synchronní buck. Měnič je zkonstruován s využitím MOSFET tranzistorů na bázi silikon karbidu. Tato práce se věnuje analýze měniče s cílem navrhnout a realizovat řídící jednotku umožňující jak zpětnovazební regulaci měniče, tak řízení v otevřené smyčce. Za tímto účelem je odvozen analytický model měniče coby dynamického systému, který je použit pro návrh a simulaci řízení. Kontrolní jednotka je implementována s využitím 32 bitového mikrořadiče založeného na architektuře ARM. V této práci je poskytnut popis a použití klíčových periférií mikrořadiče pro realizaci řízení. Na závěr jsou shrnuty výsledky měření dynamického chování výkonových tranzistorů při provozu měniče. Pozornost je především věnována měření proudu tekoucího jedním tranzistorem s využitím běžného rezistoru pro snímání proudu a kompenzaci frekvenční charakteristiky rezistoru.This master degree thesis is concerned with the design of high power converter. The converter is based on synchronous buck topology and is realized using silicon carbide MOSFET transistors. This work deals with an analysis of such type of converter to design and realize a control unit providing feedback control of the converter. Therefore, a dynamic model of the converter is derived using a conventional technique of averaged state space modeling. The derived model is used for controller design and closed-loop control simulation. The control unit is implemented using a 32-bit ARM-based microcontroller. Hence, an insight into the microcontroller key peripherals is provided as well as a brief overview of the firmware architecture. This work concludes by a brief investigation of switching waveforms of SiC MOSFETs acquired during the converter operation. Attention is called to a transistor current measurement with a low-cost current sensing resistor and its frequency characteristic compensation

Assessment of novel power electronic converters for drives applications

Phd ThesisIn the last twenty years, industrial and academic research has produced over one hundred new converter topologies for drives applications. Regrettably, most of the published work has been directed towards a single topology, giving an overall impression of a large number of unconnected, competing techniques. To provide insight into this wide ranging subject area, an overview of converter topologies is presented. Each topology is classified according to its mode of operation and a family tree is derived encompassing all converter types. Selected converters in each class are analysed, simulated and key operational characteristics identified. Issues associated with the practical implementation of analysed topologies are discussed in detail. Of all AC-AC conversion techniques, it is concluded that softswitching converter topologies offer the most attractive alternative to the standard hard switched converter in the power range up to 100kW because of their high performance to cost ratio. Of the softswitching converters, resonant dc-link topologies are shown to produce the poorest output performance although they offer the cheapest solution. Auxiliary pole commutated inverters, on the other hand, can achieve levels of performance approaching those of the hard switched topology while retaining the benefits of softswitching. It is concluded that the auxiliary commutated resonant pole inverter (ACPI) topology offers the greatest potential for exploitation in spite of its relatively high capital cost. Experimental results are presented for a 20kW hard switched inverter and an equivalent 20kW ACPI. In each case the converter controller is implanted using a digital signal processor. For the ACPI, a new control scheme, which eliminates the need for switch current and voltage sensors, is implemented. Results show that the ACPI produces lower overall losses when compared to its hardswitching counterpart. In addition, device voltage stress, output dv/dt and levels of high frequency output harmonics are all reduced. Finally, it is concluded that modularisation of the active devices, optimisation of semiconductor design and a reduction in the number of additional sensors through the use of novel control methods, such as those presented, will all play a part in the realisation of an economically viable system.Research Committee of the University of Newcastle upon Tyn

Industrial and Technological Applications of Power Electronics Systems

The Special Issue "Industrial and Technological Applications of Power Electronics Systems" focuses on: - new strategies of control for electric machines, including sensorless control and fault diagnosis; - existing and emerging industrial applications of GaN and SiC-based converters; - modern methods for electromagnetic compatibility. The book covers topics such as control systems, fault diagnosis, converters, inverters, and electromagnetic interference in power electronics systems. The Special Issue includes 19 scientific papers by industry experts and worldwide professors in the area of electrical engineering

Power Management Electronics

Accepted versio

Resonant Behaviour of Pulse Generators for the Efficient Drive of Optical Radiation Sources Based on Dielectric Barrier Discharges

Excimer-Lampen basierend auf Dielektrisch Behinderten Entladungen (DBD) sind effiziente Quellen ultravioletter Strahlung. Diese Arbeit verbindet theoretische Betrachtungen mit der praktischen Verifikation neu entwickelter Topologien und Betriebsmodi, um DBEs effizient mit kurzen Hochspannungspulsen zu betreiben. Durch transformatorlose Topologien und Nutzung von SiC Leistungshalbleitern konnten Effizienzen von bis zu 92 % und Pulsfrequenzen von bis zu 3.1 MHz erreicht werden