http://lbk.fe.uni-lj.si/pdfs/tibt2015.pdf

Electroporation-based applications in biotechnology.

Fossil resources-free sustainable development can be achieved through a transition to bioeconomy, an economy based on sustainable biomass-derived food, feed, chemicals, materials, and fuels. However, the transition to bioeconomy requires development of new energy-efficient technologies and processes to manipulate biomass feed stocks and their conversion into useful products, a collective term for which is biorefinery. One of the technological platforms that will enable various pathways of biomass conversion is based on pulsed electric fields applications (PEF). Energy efficiency of PEF treatment is achieved by specific increase of cell membrane permeability, a phenomenon known as membrane electroporation. Here, we review the opportunities that PEF and electroporation provide for the development of sustainable biorefineries. We describe the use of PEF treatment in biomass engineering, drying, deconstruction, extraction of phytochemicals, improvement of fermentations, and biogas production. These applications show the potential of PEF and consequent membrane electroporation to enable the bioeconomy and sustainable development.

/pdf/energy-efficient-biomass-processing-with-pulsed-electric-2xjj22y5tx.pdf

Energy-efficient biomass processing with pulsed electric fields for bioeconomy and sustainable development

A solid-state linear transformer driver stack has been developed to demonstrate pulsed power generation and output pulse shaping. It consists of 30 modules each using 24 power metal–oxide–semiconductor field-effect transistors as switches. The output voltage of the stack is the superposition of the voltage pulse of each module no matter if the modules are switched synchronously or not. In synchronous operation, the output voltages of all modules are added up to reach an output voltage up to \(\sim 29\) kV with a maximum output current of \(\sim 240\) A. The pulsewidth is variable in the range of 50–170 ns. On the other hand, by carrying out separate switching of different modules, the output waveform can be varied by performing pulse shaping. The control signals for pulse shaping experiment are generated using an field-programmable gate array board that allows potentially automatic waveform optimization.

Pulsed Power Generation by Solid-State LTD

This paper describes the circuit of a capacitor charger for a solid-state Marx modulator. A high-efficiency LCC resonant inverter is proposed for the simultaneous charging of many capacitors in parallel using a multistage transformer and rectifier. Using a high-voltage insulation cable, the charging loop, which represents the primary winding of transformer, is implemented to transfer the power from the resonant inverter to each stage. In addition to the simultaneous charging of separate capacitors, the advantages of the proposed circuit and structure include compact design and reliable insulation performance against high-voltage pulses. Based on the relevant approximation, the simplified analysis of an LCC resonant converter with a trapezoidal shape of resonant current is provided and a 50-kW high-voltage capacitor charger is designed for a 40-kV solid-state Marx modulator. The power stage, which consists of a transformer with four voltage-doubled rectifiers, is designed, and six power stages are configured for generating a pulse output of 40 kV. The detailed implementation of the multistage transformer and rectifier is presented in accordance with the design requirements of a high voltage modulator. Finally, the developed charger achieves 96% of the maximum efficiency and 0.96 of the maximum power factor. The experimental results verify that the proposed circuit and structure can be effectively used for a solid-state Marx modulator.

Trapezoidal Approximation of LCC Resonant Converter and Design of a Multistage Capacitor Charger for a Solid-State Marx Modulator

Das Institut fur Hochleistungsimpuls- und Mikrowellentechnik (IHM) arbeitet auf dem Gebiet der Hochleistungsimpuls- und Hochleistungsmikrowellentechnologie. Sowohl die Forschung und Entwicklung von Hochleistungsquellen als auch die damit verbundenen Anwendungen stehen im Fokus.

/pdf/annual-report-2016-institute-for-pulsed-power-and-microwave-124lskrdb0.pdf

Annual Report 2016 / Institute for Pulsed Power and Microwave Technology / Institut für Hochleistungsimpuls- und Mikrowellentechnik. (KIT Scientific Reports ; 7745)

For fast pulse generators using pulse-forming lines for energy storage, a fast MOSFET is employed as switch. It needs to have the capability of switching on the current within a short rise time. Fast switching of MOSFET requires the gate driver next to MOSFET in order to minimize the inductance. To increase the voltage switching capability of a MOSFET switch, several MOSFETs are switched in series. For such a configuration, a synchronous switching of MOSFETs is crucial. Hence, the gate drive circuitry needs to be designed to have equal propagation delay for each MOSFET. The circuitry for two stages of a stacked MOSFET switch including power supply and trigger circuit is designed, set up, and tested. The paper describes some design considerations and shows the results of some first tests.

Sebastian Keipert

Papers

Design Considerations for a Fast Stacked-MOSFET Switch