Many practical systems involve sensors that provide signals at slow sample rates. Guaranteeing the intersample performance is a fundamental problem in controlling such systems. Two multirate model predictivecontrol s...
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Many practical systems involve sensors that provide signals at slow sample rates. Guaranteeing the intersample performance is a fundamental problem in controlling such systems. Two multirate model predictivecontrol schemes are presented as solutions to this problem. In the first control scheme, intersample responses are estimated and used as compensation for the missing measurements of the controlled output. This scheme can therefore operate at the desired fast rate. The second scheme updates the control action at the slow rate that the output is sampled, but it is different from conventional techniques. This scheme finds intersample responses using a modified Z transform, and produces the control variable by optimising a performance index that accounts for both sample and intersample behaviour. Numerical simulations demonstrate that the two multirate algorithms exhibit improved time responses compared to the conventional approach.
Three recent publications proposed modifications to the generalised predictivecontrol algorithm which guarantee closed-loop stability. Of these the first two adopt the same philosophy, namely that of constrained rece...
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Three recent publications proposed modifications to the generalised predictivecontrol algorithm which guarantee closed-loop stability. Of these the first two adopt the same philosophy, namely that of constrained receding horizon predictivecontrol (CRHPC), whereas the third adopts a stable generalised predictivecontrol (SGPC) strategy by first stabilising then controlling the plant. The purpose of the paper is to examine the relationship between CRHPC and SGPC. It is shown that, theoretically, the two approaches are equivalent. but is is also shown that CRPHPC could be subject to significant numerical instability problems. Two alternative improved implementations of CRHPC are proposed, but SGPC is shown to have the advantage in terms of numerical stability and computational efficiency.
The building sector consumes a substantial portion of the world's energy, surpassing other sectors. In the non-residential area, heating, ventilation, and air conditioning systems contribute the predominant share ...
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ISBN:
(纸本)9798350349740;9798350349757
The building sector consumes a substantial portion of the world's energy, surpassing other sectors. In the non-residential area, heating, ventilation, and air conditioning systems contribute the predominant share of energy demand, with heating being the foremost consumption item. This paper assesses the design and simulation of two predictive control algorithms aimed at regulating the indoor temperature of an office building to a desired level. The aim is to maintain indoor temperature at a comfortable temperature while simultaneously minimizing energy consumption during the working period. The first algorithm employed is adaptive generalized predictivecontrol, integrated into an adaptive framework that encompasses system identification and a real-time predictivecontroller for parameters. The second algorithm is predictive functional control, involving the utilization of a discretized model of the process. Both control methods fall under the category of advanced control, capitalizing on predictive insights into the future behavior of the heating system, considering external temperature and potential perturbations. The simulation results in the paper utilize the SIMBAD Matlab toolbox, revealing a notable characteristic of the control strategies: its ability to achieve a balance between robustness and performance, even in the presence of environmental disturbances.
Nowadays, the power industry widely uses distributed generators (DG) located in close proximity to energy consumers. These generators can operate both in the isolated (island) mode for allocated load, and in parallel ...
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ISBN:
(纸本)9781538681190
Nowadays, the power industry widely uses distributed generators (DG) located in close proximity to energy consumers. These generators can operate both in the isolated (island) mode for allocated load, and in parallel with the centralized electric power system (EPS). The article describes a model of an electric power supply system (EPSS) with turbo- and a diesel-generators (TG and DiesG, respectively) with their respective controllers, as well as the results of modelling the transition of turbo-generators to the island mode upon the loss of connection with a power-feeding electric power system and connection of a diesel-generator. Modelling was performed using the MATLAB simulation software with the Simulink and SimPowerSystems packages. From the modelling results, the following conclusions can be drawn: transition to the island mode and the connection of additional high load, as well as turbo-generator overloading, lead to power-fail and frequency drop in the electric power supply system. Connecting and synchronizing a diesel-generator with a turbo-generator provides the stabilization of voltage and frequency at bus bars of the turbo-generator and of the parameters of the electric power supply system operation. The application of the predictivecontrol approach for turbo-generator controllers, provides for a significant reduction of the system response, reducing the risk of excessive correction and mitigating voltage and frequency fluctuations at the shutdown of the power-feeding electric power system after connecting an additional heavy load.
The efficiency issue of energy systems in the oil and gas industry is a crucial factor nowadays. Energy share in the production costs of oil and gas can reach 50%. Among the most important energy equipment are the ele...
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The efficiency issue of energy systems in the oil and gas industry is a crucial factor nowadays. Energy share in the production costs of oil and gas can reach 50%. Among the most important energy equipment are the electric drives of the pumps, compressors, auxiliary units, etc. The paper considered the lifecycle of the electric drives used at oil and gas fields and evaluated their efficiency parameters during periods of operational wear or malfunctioning. At the same time, the lifecycle of the energy equipment was seen as its technical state during operation. Based on the spectral analysis of the current using the finite Fourier transform (FFT), the main frequency components were identified that characterize the type and level of malfunction, taking into account defined efficiency indicators of the electric drive. A technique for assessing the technical state of an electric drive was proposed based on the normalized levels of the amplitudes of the frequency components. predictive management of the electric drive was implemented in terms of correcting the control system when a malfunction occurs, providing the required efficiency indicators. Boundaries for the technical state of the electric drive were determined. Recommendations for further operation, terms of maintenance and repair or preventive management were presented.
The widespread use of distributed generation (DG) plants in cyber-physical power supply systems (CPPSS) requires solving the complex problem of setting their regulators. The presented study aimed to determine the perf...
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The widespread use of distributed generation (DG) plants in cyber-physical power supply systems (CPPSS) requires solving the complex problem of setting their regulators. The presented study aimed to determine the performance of the group predictive voltage and frequency regulators of DG plants in CPPSS. These studies were conducted in the MatLab environment on the CPPSS models with gas turbine units and with a small-scale hydroelectric power plant. The proposed method for tuning group predictive regulators makes it possible to improve the quality control indices. The research has established that with an additional load connected, the maximum voltage dip is reduced by a factor of 3.5 compared to conventional control regulators. In addition, the time of a transient process for the generator rotor speed is decreased by a factor of 3. In the case of a short-term short circuit, predictive regulators can reduce the time of the transient process by a factor of 1.5 and the overshoot by more than 2 times. The simulation results have confirmed the efficiency of group predictive regulators when used in DG plants, i.e., improvement of the quality of control processes in various operating modes.
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