• Journal of Power Electronics
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• v.17 no.4
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• pp.983-990
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• 2017

This paper proposes a model predictive control based on the discrete Lyapunov function to improve the performance of power electronic converters. The proposed control technique, based on the finite control set model predictive control (FCS-MPC), defines a cost function for the control law which is determined under the Lyapunov stability theorem with a control error compensation. The steady state and dynamic performance of the proposed control strategy has been tested under a single phase AC/DC voltage source rectifier (S-VSR). Experimental results demonstrate that the proposed control strategy not only offers global stability and good robustness but also leads to a high quality sinusoidal current with a reasonably low total harmonic distortion (THD) and a fast dynamic response under linear loads.

• Journal of Power Electronics
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• v.18 no.6
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• pp.1791-1804
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• 2018

To achieve a fast dynamic response and to solve the multi-objective control problems of the output currents, capacitor voltages and system constraints, this paper proposes a deadbeat and hierarchical predictive control with space-vector modulation (DB-HPC-SVM) for five-level nested neutral point piloted (NNPP) converters. First, deadbeat control (DBC) is adopted to track the reference currents by calculating the deadbeat reference voltage vector (DB-RVV). After that, all of the candidate switching sequences that synthesize the DB-RVV are obtained by using the fast SVM principle. Furthermore, according to the redundancies of the switch combination and switching sequence, a hierarchical model predictive control (MPC) is presented to select the optimal switch combination (OSC) and optimal switching sequence (OSS). The proposed DB-HPC-SVM maintains the advantages of DBC and SVM, such as fast dynamic response, zero steady-state error and fixed switching frequency, and combines the characteristics of MPC, such as multi-objective control and simple inclusion of constraints. Finally, comparative simulation and experimental results of a five-level NNPP converter verify the correctness of the proposed DB-HPC-SVM.

• Nutrition Research and Practice
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• v.18 no.2
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• pp.210-222
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• 2024

BACKGROUND/OBJECTIVES: Chronic renal failure (CRF) is a complex pathological condition that lacks a cure. Certain Chinese medicines, such as melittin, a major component in bee venom, have shown efficacy in treating CRF patients. On the other hand, the mechanisms underlying the therapeutic effects of melittin are unclear. MATERIALS/METHODS: A 5/6 nephrectomy model (5/6 Nx) of renal failure was established on rats for in vivo assays, and mouse podocyte clone 5 (MPC5) mouse podocyte cells were treated with angiotensin II (AngII) to establish an in vitro podocyte damage model. The 24-h urine protein, serum creatinine, and blood urea nitrogen levels were evaluated after one, 2, and 4 weeks. Hematoxylin and eosin staining, Masson staining, and periodic acid-Schiff staining were used to examine the pathological changes in kidney tissues. A cell counting kit 8 assay was used to assess the cell viability. Reverse transcription polymerase chain reaction and Western blot were used to assess the mRNA and protein levels in the cells, respectively. RESULTS: In the rat 5/6 Nx, melittin reduced the 24-h urinary protein excretion and the serum creatinine and blood urea nitrogen levels. Furthermore, the renal pathology was improved in the melittin-treated 5/6 Nx rats. Melittin promoted podocin, nephrin, Beclin 1, and the LC3II/LC3I ratio and inhibited phosphorylated mammalian target of rapamycin (mTOR)/mTOR in 5/6 Nx-induced rats and AngII-induced MPC5 mouse podocyte cells. Moreover, inhibiting autophagy with 3-MA weakened the effects of melittin on podocin, nephrin, and the LC3II/LC3I ratio in podocytes. CONCLUSION: Melittin may offer protection against kidney injury, probably by regulating podocyte autophagy. These results provide the theoretical basis for applying melittin in CRF therapy.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.11
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• pp.1128-1136
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• 2007

This paper presents an application study of a model predictive control based commercial package PCTP to real chemical processes. The first case study concerns a product purity control of a splitter process which distillates styrene from undesired component ethyl-benzene produced from ethyl-benzene dehydrogenation reaction. The second case study is about a temperature control of ethyl-benzene dehydrogenation reactor and an excess oxygen control of the fired heater. Optimum control structure for MPC application is developed for each case study. The application results show a significant improvement in control performance and stability.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.12
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• pp.2285-2290
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• 2008

Even though efficiency of coal-fired power plant is proportional to operating temperature, increasement of operating temperature is limited by a technological level of each power plant component. It is an alternative plan to increase operating pressure up to ultra super critical point for efficiency enhancement. It is difficult to control process of power plant in ultra super critical point because that point has highly nonlinear characteristics. In this paper, new control logic, Unit Response Optimizer Controller(URO Controller) which is based on Fuzzy logic and Model Predictive Controller, is introduced for better performance. Then its performance is tested and analyzed with design guideline.

• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1241-1250
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• 2018

Parallel three-phase voltage source inverters in a direct connection configuration are widely used to increase system power ratings. A zero-sequence circulating current can be generated according to the switching method; however, the zero-sequence circulating current not only distorts current, but also reduces the system reliability and efficiency. In this paper, a model predictive control scheme is proposed for parallel inverters to drive an interior permanent magnet synchronous motor with zero-sequence circulating current suppression. The voltage vector of the parallel inverters is derived to predict and control the torque and stator flux components. In addition, the zero-sequence circulating current is suppressed by designing the cost function without an additional current sensor and high-impedance inductor. Simulation and experimental results are presented to verify the proposed control scheme.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.524-529
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• 2004

In this paper, We described the method which developed the optimal control system for air separation unit to change production rates frequently and rapidly. Control models of the process were developed from actual plant data using subspace identification method which is developed by many researchers in resent years. The model consist of a series connection of linear dynamic block and static nonlinear block (Wiener model). The model is controlled by model based predictive controller. In MPC the input is calculated by on-line optimization of a performance index based on predictions by the model, subject to possible constraints. To calculate the optimal the performance index, conditions are expressed by LMI(Linear Matrix Inequalities).In order to access at the Bailey DCS system, we applied the OPC server and developed the Client program. The OPC sever is a device which can access Bailey DCS system.The Client program is developed based on the Matlab language for easy calculation,data simulation and data logging. Using this program, we can apply the optimal input to the DCS system at real time.

• International Journal of Control, Automation, and Systems
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• v.3 no.2
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• pp.252-257
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• 2005

In this work, we propose a simple but efficient method to design a target temperature trajectory for pulling speed tracking control of the crystal grower in the Czochralski crystallization process. In the suggested method, the model predictive control strategy is used to incorporate the complex dynamic effect of the heater temperature on the pulling speed into the temperature trajectory design quantitatively. The feedforward trajectories designed by the proposed method were implemented on 200 mm and 300 mm silicon crystal growers in the commercial Czochralski process. The application results have demonstrated its excellent and consistent tracking performance of pulling speed along whole bulk crystal growth.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1211-1214
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• 2004

In this paper, we propose to use variable inlet guide vane as a means of active surge control to solve above problems. There is some advantage. For example, since the inlet guide vanes are already present in POSCO, no additional actuation device is required. We can collect all data easily which is related to the test and can simulate new model using our compressors. We can obtain the result that blow-off valve is opened less 5% and can operate air compressor automatically and more efficiently. Through a simulation example, the effectiveness of the proposed schemes is illustrated.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.323-326
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• 2003

The rural simulation model is necessary to do a effective rural planing. And it is considered to objected-oriented concept because rural are composed of facilities which have organic relations each other. For constituting object, classify rural facilities. In existing study, rural resource is consists of 2 fields including 14 categories, specially rural facility is configured with 20 categories which is represented three geometric element factor. Rural is a group which constructed to multi-layer facilities. So constitute object structure with 4 steps and 5 layers using MPC model.