Analytical Derivation of the AC-Side Input Admittance of a Modular Multilevel Converter With Open- and Closed-Loop Control Strategies

2018 ◽  
Vol 33 (1) ◽  
pp. 248-256 ◽  
Author(s):  
Mebtu Beza ◽  
Massimo Bongiorno ◽  
Georgios Stamatiou
Keyword(s):  
Closed Loop ◽  
Control Strategies ◽  
Closed Loop Control ◽  
Modular Multilevel Converter ◽  
Multilevel Converter ◽  
Input Admittance ◽  
Loop Control ◽  
Analytical Derivation

Research on the Control Method of STATCOM Based on MMC

2013 ◽  
Vol 448-453 ◽  
pp. 2167-2170
Author(s):  
Kai Li ◽  
Yi Hui Zheng ◽  
Xin Wang ◽  
Li Xue Li ◽  
Gang Yao ◽  
...  
Keyword(s):  
Closed Loop ◽  
Reactive Power ◽  
Control Method ◽  
Modular Multilevel Converter ◽  
Energy Balancing ◽  
Multilevel Converter ◽  
Voltage Fluctuation ◽  
Loop Control ◽  
Voltage Balancing ◽  
High Voltage Direct Current

To realize the STATCOM based on Modular Multilevel Converter (MMC), a simplified double-closed loop structure, simplifying from the control method of High Voltage Direct Current (HVDC) based on MMC, is presented. Considering MMCs DC side using capacitors, a part-controlling method based on energy balancing is proposed, to solve the voltage balancing problem. With the part-controlling fixing the changing capacitors voltage and the simplified double-closed loop control method, voltage fluctuation could be reduced, and the loads reactive power could be compensated. The correctness and the effectiveness of the MMC-STATCOM controlling scheme is verified by Matlab/Simulink.

EVALUATION OF CLOSED-LOOP CONTROL SYSTEM FOR RESTORING STANDING AND SITTING FUNCTIONS BY FUNCTIONAL ELECTRICAL STIMULATION

2005 ◽  
Vol 17 (01) ◽  
pp. 19-26 ◽  
Author(s):  
CHENG-LIANG LIU ◽  
CHUNG-HUANG YU ◽  
SHIH-CHING CHEN ◽  
CHANG-HUNG CHEN
Keyword(s):  
Electrical Stimulation ◽  
Functional Electrical Stimulation ◽  
Closed Loop ◽  
Spinal Cord Injuries ◽  
Control Method ◽  
Control Strategies ◽  
Evaluation Process ◽  
Closed Loop Control ◽  
Loop Control ◽  
Loop Control System

Functional electrical stimulation (FES) is a method for restoring the functional movements of paraplegic or patients with spinal cord injuries. However, the selection of parameters that control the restoration of standing up and sitting functions has not been extensively investigated. This work provides a method for choosing the four main items involved in evaluating the strategies for sit-stand-sit movements with the aid of a modified walker. The control method uses the arm-supported force and the angles of the legs as feedback signals to change the intensity of the electrical stimulation of the leg muscles. The control parameters, Ki and Kp, are vary for different control strategies. Four items are collected through questionnaires and used for evaluation. They are the maximum reactions of the two hands, the average reaction of the two hands, largest absolute angular velocity of the knee joints, and the sit-stand-sit duration time. The experimental data are normalized to facilitate comparison. Weighting factors are obtained and analyzed from questionnaires answered by experts and are added to evaluation process for manipulation. The results show that the best strategy is the closed-loop control with parameters Ki=0.5 and Kp=0.

scholarly journals Neural Network-Based State Estimation for a Closed-Loop Control Strategy Applied to a Fed-Batch Bioreactor

Complexity ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Santiago Rómoli ◽  
Mario Serrano ◽  
Francisco Rossomando ◽  
Jorge Vega ◽  
Oscar Ortiz ◽  
...  
Keyword(s):  
Neural Network ◽  
Closed Loop ◽  
Rbf Neural Network ◽  
Control Strategies ◽  
Tracking Error ◽  
Closed Loop Control ◽  
Online Information ◽  
Fed Batch ◽  
Loop Control ◽  
Batch Bioreactor

The lack of online information on some bioprocess variables and the presence of model and parametric uncertainties pose significant challenges to the design of efficient closed-loop control strategies. To address this issue, this work proposes an online state estimator based on a Radial Basis Function (RBF) neural network that operates in closed loop together with a control law derived on a linear algebra-based design strategy. The proposed methodology is applied to a class of nonlinear systems with three types of uncertainties: (i) time-varying parameters, (ii) uncertain nonlinearities, and (iii) unmodeled dynamics. To reduce the effect of uncertainties on the bioreactor, some integrators of the tracking error are introduced, which in turn allow the derivation of the proper control actions. This new control scheme guarantees that all signals are uniformly and ultimately bounded, and the tracking error converges to small values. The effectiveness of the proposed approach is illustrated on the basis of simulated experiments on a fed-batch bioreactor, and its performance is compared with two controllers available in the literature.

scholarly journals Control of Flexible Manipulator Systems

1996 ◽  
Vol 210 (2) ◽  
pp. 113-130 ◽  
Author(s):  
M O Tokhi ◽  
A K M Azad
Keyword(s):  
Closed Loop ◽  
Control Strategies ◽  
Open Loop ◽  
Flexible Manipulator ◽  
Closed Loop Control ◽  
Loop Control ◽  
Acceleration Feedback ◽  
Low Pass ◽  
Input Torque ◽  
Collocated Control

This paper presents an investigation into the development of open-loop and closed-loop control strategies for flexible manipulator systems. Shaped torque inputs, including Gaussian-shaped and low-pass (Butter-worth and elliptic) filtered input torque functions, are developed and used in an open-loop configuration and their performance studied in comparison to a bang-bang input torque through experimentation on a single-link flexible manipulator system. Closed-loop control strategies that use both collocated (hub angle and hub velocity) and non-collocated (end-point acceleration) feedback are then proposed. A collocated proportional and derivative (PD) control is first developed and its performance studied through experimentation. The collocated control is then extended to incorporate, additionally, non-collocated feedback through a proportional integral derivative (PID) configuration. The performance of the hybrid collocated and non-collocated control strategy thus developed is studied through experimentation. Experimental results verifying the performance of the developed control strategies are presented and discussed.

Trajektorienbasierte Strategie für die Regelung des Tiefziehprozesses während des Hubes*/Trajectory-based closed loop control for controlling deep-drawing process

2016 ◽  
Vol 106 (10) ◽  
pp. 684-689
Author(s):  
M. Prof. Liewald ◽  
M. Barthau ◽  
S. Braun
Keyword(s):  
Deep Drawing ◽  
Closed Loop ◽  
Control Strategies ◽  
Closed Loop Control ◽  
Drawing Process ◽  
Control Loop ◽  
Deep Drawing Process ◽  
Loop Control ◽  
Control Intervention ◽  
Measurement Devices

Am IFU der Universität Stuttgart wurde ein Regelkreis für das Tiefziehen entwickelt, welcher einen regelnden Eingriff in den Tiefziehvorgang während des Hubes erlaubt. Die Umsetzung dieses Regelungskonzeptes erfolgte mittels eines Ziehwerkzeugs, das an eine vereinfachte Geometrie eines PKW-Vorderkotflügels angelehnt ist. Beschrieben werden die messtechnische Ausstattung des Versuchswerkzeugs, der Aufbau des Regelkreises und die Entwicklung der Regelstrategie. Des Weiteren werden die Ergebnisse der Simulation sowie der ersten Versuche dargestellt.   At IFU, University of Stuttgart a control loop for deep-drawing process, with control intervention during deep-drawing stroke was developed. The closed-loop control was demonstrated on a fender shaped geometry. Described are the measurement devices, design of the closed-loop and the featured control strategies. Results of simulation and sensitivity analysis are also shown.

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