Bart Roodenburg

Electrochemical reactions and electrode corrosion in pulsed electric field (PEF) treatment chambers

Abstract In Pulsed Electric Field systems for preservation of liquid food, electrochemical reactions can occur in the treatment chamber. This may result in partial electrolysis of the solution, in corrosion of the electrode and in introduction of small particles of electrode material in the liquid. This contribution will describe the phenomena that occur at the electrodes. The ultimate objective is to be able to adapt the design and the pulse waveform such that these phenomena are minimised. After revisiting the basic theory on electrochemical reactions, an equivalent circuit is presented that can be used to model an electrochemical cell. Based on these models it is shown that electrode corrosion can be limited with short enough pulses. The theory has been verified by experiments. The results of these experiments are presented in this contribution.

Series arc extinction in DC microgrids using load side voltage drop detection

Due to the absence of current zero crossing, dc arcs do not extinguish as easily as ac ones. It is essential to detect and eliminate series arc faults in dc microgrids in order to ensure safety, particularly while unplugging loads. Several detection and extinction methods using various means are known in literature. In this paper a novel arc detection method is proposed. It detects the load side input voltage drop due to the initial electrode specific minimum arc voltage. Only the local input voltage has to be measured and selectivity is given. The arc can be extinguished by shutting down the loads power electronics converter. The proposed method is elaborated through simulation of arc behaviour for constant resistor and constant power loads with input capacitors. First experimental results correspond with the theoretical analysis.

Conductive Carbon Loaded Polymer Film Electrodes for Pulsed-Power Applications. Part I: Determination of the Film Properties

Abstract Electrically conductive polymer composites consisting of a nonconductive polymer matrix and conductive fillers, such as carbon black, are widely used. This contribution describes the specific electrical properties of polymer composite films for pulsed conditions in the microsecond (10−6 s) range. Investigation of an industrially available volume conductive polymer film (Carbostat) showed that the electrical properties of this material, which can be considered for electrodes in pulsed power applications, are quite different from the properties for DC conditions.

Technology for preservation of food with pulsed electric fields (PEF)

Food can be preserved with pulses of electric fields with a magnitude of 10 to 50 kV/cm and a duration of 1 to 10 /spl mu/s. To apply this technique both a treatment chamber (applicator) and an electronic pulse generator is required. In this paper an overview is given of types of pulse generators for pulsed electric fields (PEF). Further limitations of the technology as imposed by the limited switching power of switches are discussed with respect to the availability of switches.

Conductive Carbon Loaded Polymer Film Electrodes for Pulsed Power Applications. Part II: Determination and Minimization of the Contact Resistance

Abstract Electrically conductive polymer composites consisting of a nonconductive polymer matrix and conductive fillers, such as carbon black, are widely used. This contribution describes a newly developed measurement setup that has been built to investigate the specific electrical properties of polymer composite films for pulsed conditions in the microsecond (10−6 s) range. For an industrially available volume conductive polymer film (Carbostat) the contact resistivity to copper has been investigated. Also, three methods for minimizing the contact resistivity, namely pressing, gluing, and wetting, have been compared for a wide range of applied current densities.