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4. Hybrid Sensor Fault Tolerant Control of Low Voltage DC Microgrid

Author

Chandra, M. V. Satya Sai and Mohapatro, Sankarsan

Abstract

Low voltage DC (LVDC) microgrids have recently gained popularity. In applications such as rural electrification, data center power systems, and satellite microgrids stand-alone LVDC microgrids have proven to be extremely beneficial. In the case of standalone LVDC microgrids, voltage control and energy management are crucial. In such standalone and safety-critical systems, sensor faults are especially important to address. Therefore, we present a hybrid sensor fault tolerant control (HSFTC) approach with redundancy features at the software and hardware levels. To address voltage sensor failures, an analytical redundancy component employs a sliding mode observer in conjunction with adaptive passivity-based control. To overcome battery current sensor failures, a double modular hardware redundancy component is included. Both MATLAB simulations and hardware experiments on the microgrid testbed are used to verify the performance of this HSFTC in a variety of scenarios involving sensor malfunctions and load disturbances. We observe that the suggested HSFTC can address sensor faults and load disturbances simultaneously. The effectiveness of our control approach in dealing with sensor malfunctions is evaluated in comparison to reference control strategies.

Published
2024
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5. Spike Electrode-Based DBD Reactor for Improved Electric Discharge Power Toward Better Diesel Engine Exhaust Treatment at Low Applied Voltage

Author

Bhattacherjee, Sarbesh and Mohapatro, Sankarsan

Abstract

Concern has been raised recently by the increasing usage of diesel engines in both the automotive and industrial sectors. Due of the strict emission regulations, it will be challenging to economically manage exhaust using solely conventional methods. Alternative methods such as electric discharge-based diesel engine exhaust (DEE) treatment have become more popular; however, because this technology requires high voltage, its application in automobiles is restricted. In this study, a dielectric barrier discharge (DBD) reactor with a spike electrode arrangement is suggested for the treatment of diesel exhaust. NOX removal from 5-kVA DEE is evaluated using two types of symmetrical and asymmetrical spike electrode-based DBD reactors in comparison to plane electrode-based DBD. It has been found that while using 50-Hz ac at a lower applied voltage, a spike-configured electrode can inject more power than a plane electrode. As a result, nitric oxides are removed more effectively at lower applied voltages. This research will contribute to the implementation of non-thermal plasma (NTP)-based exhaust treatment in the automotive industry. When compared to other types of electrodes at lower applied voltages, the asymmetrical spike electrode-based DBD with a 10-mm spacing between spikes demonstrated superior NO elimination. Simulation study for electric field of each electrode configuration was conducted using COMSOL Multiphysics and it was in line with the experimental results. The experiments were conducted at 5 L/min keeping the load on the diesel engine at 80%.

Published
2024
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13. Feasibility of Artificial Neural Networks and Fuzzy Logic Models for Prediction of NO $_{X}$ Concentrations in Nonthermal Plasma-Treated Diesel Exhaust.

Author

Allamsetty, Srikanth and Mohapatro, Sankarsan

Subjects
*FUZZY neural networks, *ARTIFICIAL neural networks, *MULTILAYER perceptrons, *FUZZY logic, *PREDICTION models, *NON-thermal plasmas
Abstract

High-voltage discharge-based nonthermal plasma (NTP) treatment for diesel exhaust is a laboratorial proven efficient technique. A prophecy of the treatment results based on the knowledge of its parameters would be a step forward toward bringing it into real-time applications of pollution control. In this paper, artificial neural networks (ANNs) and fuzzy logic model (FLM) have been used to model the NO $_{ X }$ (sum of NO and NO2) concentrations as a function of parameters of the NTP process. A data set of 4032 input–output pairs has been collected by conducting experiments, in which 70% of the data are used for the training of the models derived. The performances of all the considered models have been evaluated by testing them for the remaining 30% of the data, which is novel for the models. Furthermore, a comparison of the models has been made based on the root-mean-square error (RMSE) and mean relative error (MRE), where the FLM has been found to be the better compared to the ANN-based models, i.e., ANN, multilayer perceptrons (MLP), and functional link ANN (FLANN). The RMSE of FLM is 2.53 ppm for a test data of 1210 sets. It can be said from these results that the NO $_{ X }$ concentrations can be predicted using FLM with a good accuracy. [ABSTRACT FROM AUTHOR]

Published
2019
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14. Portable HVAC and Pulsed Plasma Sources for Control of NOX in Diesel Engine Exhaust

Author

Mohapatro, Sankarsan and Rajanikanth, BS

Subjects
Electrical Engineering
Abstract

In this paper studies were carried out on two compact electric discharge plasma sources for controlling nitrogen oxides (NOX) emission in diesel engine exhaust. The plasma sources consist of an old television flyback transformer to generate high frequency high voltage ac (HVAC) and an automobile ignition coil to generate the high voltage pulses (HV Pulse). The compact plasma sources are aimed at retrofitting the existing catalytic converters with electric discharge assisted cleaning technique. To enhance NOX removal efficiency cascaded plasma-adsorbent technique has been used. Studies were reported at different flow rates and load conditions of the diesel engine.

Published
2011

15. Cascaded Cross Flow DBD-Adsorbent Technique for NOX Abatement in Diesel Engine Exhaust

Author

Mohapatro, Sankarsan and Rajanikanth, BS

Subjects
Electrical Engineering
Abstract

In this paper, a different type of cross flow dielectric barrier discharge (DBD) reactor was designed and tested. Here the gas flow is perpendicular to the barrier discharge electrode. Discharge plasma was utilized to oxidize NO contained in the exhaust gas to NO2 and subsequent NO2 removal can be improved using an adsorbent system. A detailed study of DeNO(X) in a stationary diesel engine exhaust was carried out using pulsed electrical discharges/adsorbent processes. Activated alumina (Al2O3) and MS-13x were used as adsorbents at room temperature. The main emphasis is laid on the removal of NOX from the filtered diesel engine exhaust. In filtered exhaust environment, the cross flow reactor along with adsorbent exhibits a superior performance with regard to NOX removal when compared to that with axial flow of gas. In this paper we bring out a relative comparison of discharge plasma and plasma-adsorbent process at various gas flow rates, ranging from 2 l/min to 25 l/min. The discharge plasma-adsorbent assisted barrier discharge reactor has shown promising results in NOX removal at high flow rates.

Published
2010

17. Studies on Compact Discharge Plasma Source for NOX Treatment in Engine Exhaust

Author

Mohapatro, Sankarsan and Rajanikanth, BS

Subjects
Electrical Engineering
Abstract

This paper proposes a compact electric discharge plasma source for controlling NOX emission in diesel engine exhaust. An automobile ignition coil was used to generate the high voltage pulse using flyback topology. This design is aimed at retrofitting the existing catalytic converters with pulse assisted cleaning technique. In this paper we bring out a relative comparison of discharge plasma and plasma-adsorbent process at different gas flow rates. Activated alumina was used as adsorbent. The main emphasis is laid on the development of a compact pulse source from a DC supply for the removal of NOX from the filtered diesel engine exhaust.

Published
2010

18. Corona treatment for NOx reduction from stationary diesel engine exhaust: Impact of nature of energization and exhaust composition

Author

Srinivasan, AD, Rajanikanth, BS, and Mohapatro, Sankarsan

Subjects
Electrical Engineering
Abstract

A detailed study on the removal of oxides of nitrogen (NOx) from the exhaust of a stationary diesel engine was carried out using non-thermal plasma (dielectric barrier discharge) process. The objective of the study was to explore the effect of different voltage energizations and exhaust composition on the NOx removal process. Three types of voltage energizations, namely AC, DC and Pulse were examined. Due to the ease of generation of high voltage AC/DC electrical discharges from automobile/Vehicular battery supply for possible retrofitting in exhaust cleaning circuit, it was found relevant to investigate individual energisation cases in detail for NOx removal. AC and Pulse energisations exhibit a superior NOx removal efficiency compared to DC energisation. However,Pulse energisation is found to be more energy efficient. Experiments were further carried out with filtered/ unfiltered (raw) exhaust under pulse energisations. The results were discussed with regard to NOx removal, energy consumption and formation of by-products.

Published
2009

22. Studies on \NOX Removal From Diesel Engine Exhaust Using Duct-Type DBD Reactor.

Author

Mohapatro, Sankarsan and Rajanikanth, B. S.

Subjects
*DIESEL motor exhaust gas, *NITROGEN oxides, *SEPARATION (Technology), *ELECTRIC discharges, *ELECTRIC power consumption
Abstract

With ever more stringent \NOX emissions, it is necessary to examine removal of nitrogen oxide from diesel engine exhaust. This paper describes the study of \NOX reduction from 5.9-kW stationary diesel engine exhaust under nanosecond pulse energization. Two plasma reactors characterized by dielectric barrier discharge has been designed, built, and evaluated. One of the reactor designs include nine numbers of electrodes kept in parallel, and the exhaust was allowed to pass axially, whereas the second reactor consists of nine parallel electrodes and the exhaust was allowed to pass radially. The reactors were individually tested for the treatment of nitrogen oxides for gas flow rate of 2, 5, and 10 L/min. Both the reactors have been individually tested, and results show an appreciable removal of \NOX with equal discharge volume. From the results, it was found that both the reactors were an efficient \NOX removal. With consumption of only 36 J/L, the reactors had shown a considerable 45% \DeNOX efficiency. [ABSTRACT FROM AUTHOR]

Published
2015
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23. Dielectric barrier discharge cascaded with red mud waste to enhance NOx removal from diesel engine exhaust.

Author

Mohapatro, Sankarsan and Rajanikanth, B.

Subjects
*ELECTRIC discharges, *DIELECTRICS, *DIESEL motor exhaust gas, *MUD, *NITRIC oxide, *BAUXITE, *CATALYSTS, *TEMPERATURE effect
Abstract

Red mud is a waste by-product generated during the processing of bauxite, the most common ore of aluminium. With the presence of ferric oxide, high surface area, resistance to poisoning and low cost, red mud made itself a good alternative to the existing commercial automobile catalyst. The cascading of dielectric barrier discharge plasma with red mud improved the NOX removal from diesel engine exhaust significantly. The DeNOX efficiency with discharge plasma was 74% and that with red mud was 31%. The efficiency increased to 92% when plasma was cascaded with red mud catalyst operating at a temperature of 400°C. The NOX removal was dominated by NO2 removal. The studies were conducted at different temperatures and the results were discussed. [ABSTRACT FROM AUTHOR]

Published
2012
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