12 results on '"R. T. F. Ah King"'
Search Results
2. PI Observer-based Control for Biomass Regulation under Measurement Delays
- Author
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R. T. F. Ah King, Krishna Busawon, R. Ramjug-Ballgobin, and H. C. S. Rughooputh
- Subjects
Dependency (UML) ,Observer (quantum physics) ,Robustness (computer science) ,Consistency (statistics) ,Control theory ,Control system ,Flow (psychology) ,Convergence (routing) ,PID controller ,Mathematics - Abstract
The present paper deals with the issue of measurement delays which constitute a very prominent problem faced by most control systems. The system considered is that of a bioreactor used for the biological treatment of wastewater. The recording of the output substrate concentration of such systems usually involves a delay which results from the dependency of the flow of the liquid on its consistency. A PI observer-based control is applied and its performance is analysed in terms of the maximum delay for which the system is stable and converges as well as in terms of the convergence times. Based on these parameters, the results are compared to those obtained by a feedback linearising observer-based system. This comparative analysis showed that the PI controller performed better than the feedback controller, hence confirming its efficiency in biomass regulation in the presence of delayed measurements.
- Published
- 2021
3. PI Control of Biomass Concentration for a Continuous-Discrete Bioreactor
- Author
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R. T. F. Ah King, R. Ramjug-Ballgobin, Krishna Busawon, and H. C. S. Rughooputh
- Subjects
Observer (quantum physics) ,Robustness (computer science) ,Control theory ,Convergence (routing) ,Bioreactor ,Sampling (statistics) ,Biomass ,PID controller ,Mathematics - Abstract
This paper proposes the application of a Proportional-Integral (PI) controller for the observer-based regulation of biomass concentration for a continuous-discrete system. An observer is essential to estimate the values of biomass concentration since the controller depends on these measurements. The analysis focuses on the continuous-discrete nature of the system which is represented by a continuous bioreactor system with discrete output measurements. The maximum allowable sampling partition diameter is determined along with the corresponding convergence time. These results are then compared to another work that used a feedback linearising control to achieve biomass regulation. The results obtained with the PI controller proved to be far more superior both in terms of maximum possible sampling time and convergence time. These findings confirmed the satisfactory and improved performance of the proposed observer-based controller.
- Published
- 2021
4. Optimizing Performance and Stabilizing Efficiency of a Photovoltaic Array
- Author
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Yatindra Kumar Ramgolam, R. T. F. Ah King, Vishwamitra Oree, and T. Ramjeawon
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Pyranometer ,Piping ,Power station ,business.industry ,Water flow ,Data logger ,Photovoltaic system ,Environmental science ,business ,Solar power ,Automotive engineering ,Renewable energy - Abstract
In this research work, the impact of water flow on the performance and energy output efficiency of a photovoltaic system was investigated and quantified using a method based on photovoltaic performance indicator analysis. Water flow on the surface of solar modules decreases cell temperature and soiling effects. These effects were studied on a grid-tied 2.45 kW PV system located on the roof of the Engineering Tower at the University of Mauritius. A pyranometer was connected to a data logger to monitor changes in solar power at 30 s intervals. A piping system was implemented to provide water flow on the surface of the PV modules. An infra-red thermal imager was used to study the effect of water flow on module temperature. The performance of the system under tropical climatic conditions was measured and modeled in National Renewable Energy Laboratory System Advisor Model. A financial analysis was performed to determine the viability of the water flow system. Results show that water flow enhances and stabilizes energy output efficiency. It was observed that a decrease of 30% in soiling level resulted in an increase of approximately 30% in the energy output. A financial analysis showed that implementing a water flow system on a large scale power plant will make the system cost effective and ensure optimum output efficiency.
- Published
- 2021
5. Observer-based Control of Biomass Concentration under Discrete and Delayed Measurements
- Author
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R. Ramjug-Ballgobin, H. C. S. Rughooputh, R. T. F. Ah King, and Krishna Busawon
- Subjects
Work (thermodynamics) ,Observer (quantum physics) ,Sampling (signal processing) ,Control theory ,Control system ,Control (management) ,Partition (number theory) ,Biomass ,Mathematics - Abstract
Wastewater treatment is a biological process which involves the streaming of solid waste products in tubes and makes use of sensors which provide outputs at distinct instants of time. These issues lead to problems in the control of the output, which is the substrate concentration. In this work, we present an observer and a controller which is used to control the biomass concentration of such bioreactors in the presence of delayed and discrete measurements. The aim of this paper is to make a realistic analysis of the proposed observer-based control system and conclude on the effects of delayed measurements on the maximum possible sampling partition diameter as well as to study the effect of the sampling rate on the maximum possible delay. The results obtained confirmed the satisfactory performance of the system.
- Published
- 2021
6. A PI Control Strategy for Biomass Concentration in Wastewater Treatment Plants
- Author
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Krishna Busawon, R. T. F. Ah King, R. Ramjug-Ballgobin, and H. C. S. Rughooputh
- Subjects
Steady state ,Observer (quantum physics) ,Control theory ,Control system ,Convergence (routing) ,Proportional control ,Biomass ,PID controller ,Sewage treatment ,Mathematics - Abstract
This work provides the observation and control of biomass concentration in Waste Water Treatment Plants. To achieve this, a PI controller was designed together with an observer to form an observer-based control system. The optimal values of the proportional gain and integral gain were determined to obtain the convergence of the observer in the least amount of time without compromising on the time taken by the response to reach steady state. Encouraging results which shall provide a basis for further and more in-depth research on the system were obtained.
- Published
- 2021
7. A control design methodology for SISO linear time-delay systems
- Author
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Krishna Busawon, Lei Zhang, R. Ramjug-Ballgobin, R. T. F. Ah King, and Qingwei Chen
- Subjects
Computer science ,Control theory ,Linear system ,Stability (learning theory) ,Canonical form ,State (functional analysis) ,Complex plane ,Time complexity ,Eigenvalues and eigenvectors - Abstract
This paper illustrates a control technique for single-input linear systems with delay in the state. We first proceed by introducing a novel definition of stability called Ω-stability which translate the fact that a system is stable in the Krasovskii sense over a set Ω derived from the negative real side of the complex plane. In other words, all the eigenvalues of the system lies inside the set Ω with a given stability margin. Then, for the control design, the system’s model is transformed into an extended Jordan controllable canonical form (JCCF). Based on the JCCF, we proposed a systematic construction of the controller gain such that the system under consideration becomes Ω-stable. The effectiveness of the controller is shown, via simulation, by using a typical academic example.
- Published
- 2020
8. Regulation of Biomass Concentration in Wastewater Treatment Systems under Measurement Delays
- Author
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R. Ramjug-Ballgobin, H. C. S. Rughooputh, R. T. F. Ah King, and Krishna Busawon
- Subjects
Measurement delay ,Work (thermodynamics) ,Observer (quantum physics) ,Control theory ,Control system ,Biomass ,Microbial system ,Stability (probability) ,Mathematics - Abstract
This paper proposes an observer-based control system to estimate and control biomass concentration in a simple microbial system under known output delays. More precisely, these delays are represented by time lags in the measurement of substrate concentration. We employ a feedback linearising controller that has previously been developed for a system without measurement delay. In the present work, the delay is applied to the controller and the maximum allowable delay that maintains stability is computed. Next, a nonlinear observer is proposed to predict the biomass concentration. The stability of the overall closed-loop feedback system incorporating the observer and the controller is analysed. Simulation study has revealed that the combination of the observer and controller provided a satisfactory response and was successful in regulating the biomass concentration. Finally some conclusions are drawn.
- Published
- 2020
9. Observer-based Control for Biomass Regulation under Discrete Measurements
- Author
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R. Ramjug-Ballgobin, H. C. S. Rughooputh, R. T. F. Ah King, and Krishna Busawon
- Subjects
Observer (quantum physics) ,Control theory ,Control system ,Convergence (routing) ,Sampling (statistics) ,Limit (mathematics) ,MATLAB ,Stability (probability) ,computer ,computer.programming_language ,Mathematics - Abstract
In this paper, an observer-based control system is presented for the regulation of biomass concentration in bioreactors. The importance of the observer is highlighted by the dependency of the feedback linearising controller on the measurements of biomass concentration. Further, the discrete nature of output substrate concentration is considered and the performance of the system proposed is analysed through a simulation study using Matlab/Simulink. This study is also used to determine the limit on the sampling partition diameter for which the observer and controller designed give satisfactory performance. The implemented observer-based control system showed satisfactory performance both in terms of stability and convergence for given values of sampling partition diameters.
- Published
- 2020
10. Harmonic oscillator tank: A new method for leakage and energy reduction in a water distribution network with pressure driven demand
- Author
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L. Latchoomun, Jean-Marc Ginoux, Krishna Busawon, R. T. F. Ah King, and Université des Mascareignes (UDM)
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Distribution networks ,020209 energy ,Mechanical Engineering ,Energy reduction ,02 engineering and technology ,Building and Construction ,Specific energy consumption ,Pollution ,Energy requirement ,6. Clean water ,Industrial and Manufacturing Engineering ,Volumetric flow rate ,[SPI.AUTO]Engineering Sciences [physics]/Automatic ,General Energy ,020401 chemical engineering ,Control theory ,0202 electrical engineering, electronic engineering, information engineering ,Environmental science ,0204 chemical engineering ,Electrical and Electronic Engineering ,Harmonic oscillator ,ComputingMilieux_MISCELLANEOUS ,Civil and Structural Engineering ,Efficient energy use ,Leakage (electronics) - Abstract
It is now well established that rate of leakage of water is directly related to the distribution pressure in a network. In this context, pumps can consume up to 60% of the overall energy requirement in the case of pressure driven demand whereby they are solicited for direct supply. In this paper, we investigate the energy efficiency of distribution in an experimental network which is embedded with two levels of leakage (low and high) using three different methods. They are analysed and compared in terms of specific energy consumption and rate of leakage. A novel concept known as the Harmonic Oscillator Tank has been developed whereby the conventional hydropneumatic tank is pressure modulated so as to produce a constant output flowrate within the presence of leaks. Experimental results show that the throughput of the Harmonic Oscillator Tank for a heavy leaking network is highest (86.45%) with the lowest percentage leakage of 13.5% at a specific energy consumption of only 0.354 kWh/m3/day when compared to the other two schemes namely direct pumping and pumping through a variable speed drive in a loop. This Harmonic Oscillator Tank opens up new avenues for reducing energy and leakage in old damaged networks whereby a short or medium-term solution is often required since infrastructure renewal requires time and a massive investment.
- Published
- 2020
11. Efficiency of VFD Coupled Induction Motors Operating in the Scalar Mode with Different Types of Loads
- Author
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R. T. F. Ah King, L. Latchoomun, Krishna Busawon, C. Gokhool, and J-P. Barbot
- Subjects
Physics ,Variable-frequency drive ,Control theory ,Stator ,law ,Work (physics) ,Control variable ,Torque ,Induction motor ,Slip (vehicle dynamics) ,law.invention ,Voltage - Abstract
In this paper, we investigate the behaviour of scalar controlled AC Variable Frequency Drives for induction motors when coupled with different types of loads. It is well known that slip is more pronounced at high speeds rather than low speeds in loads such as in pumps and fans operation because the torque load varies as the square or cube of the speed. Slip compensation in Voltage/Frequency controlled Variable Frequency Drives may work only up to a certain limit since the problem can be exacerbated by overcompensation causing low magnetisation flux of the stator and the Variable Frequency Drive becomes uncontrollable. In this research work, we investigate the behaviour of the motor and Variable Frequency Drive assembly with regards to slowly changing loads from low to high speeds. Results show that at reduced speeds for the Variable Frequency Drive and motor assembly, the efficiency is lowest for square and cubic torques loads compared to linear and constant torque loads. Highest efficiency and torque are achieved only in a restricted interval of speed. This problem therefore compels us to avoid using the Variable Frequency Drives in the Voltage/Frequency mode at low speeds for pumps and fans.
- Published
- 2019
12. Design of a Water Pressure Boosting System for Pressure-Driven Demand in a Distribution Network
- Author
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Krishna Busawon, R. T. F. Ah King, L. Latchooomun, T. Sockalingum, J. P. Barbot, and K. Virasamy Poulle
- Subjects
Atmospheric pressure ,Coupling (computer programming) ,Booster pump ,Flow (psychology) ,Environmental science ,Centrifugal pump ,Constant (mathematics) ,Stability (probability) ,Automotive engineering ,Efficient energy use - Abstract
In pressure-driven demand of a water distribution network, booster pumps are so much sollicited online that they can cycle on and off several times in an hour. Coupling the pumps with a variable speed drive does not offer much benefit since at reduced speeds and flows, pressure increases, shifting the operation point from the best efficiency zone. Another alternative is to use a hydropneumatic tank which reacts to pressure changes and at the same time prevents pressure fluctuations online. In this paper, we design a new version of the hydropneumatic tank system to supply water at a steady flow using a centrifugal pump coupled with a variable speed drive in order to maintain a constant air pressure inside the tank. Results of simulation show that the system can achieve higher stability and energy efficiency compared to direct pumping without compromising customer demand.
- Published
- 2018
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