Research on Voltage Oriented Control Strategy of Grid-Connected Inverter of Wind Power Generation

2013 ◽  
Vol 818 ◽  
pp. 212-217
Author(s):  
Yong Yang ◽  
Guang Ming Lan ◽  
Zhi Qi Sun ◽  
Jian Guo ◽  
Zhong Qiang Zhang
Keyword(s):  
Mathematical Model ◽  
Power Control ◽  
Closed Loop ◽  
Control Strategies ◽  
Closed Loop Control ◽  
Direct Power ◽  
Direct Power Control ◽  
Two Phase ◽  
Loop Control ◽  
Grid Connected Inverter

Based on the dynamic mathematical model of three-phase grid-connected inverter, two kinds of control strategies are compared, one is double closed loop control based on grid voltage orientation theory, the other is direct power control. According to the mathematical model of two-phase rotating coordinates of the inverter, in double closed loop control theory, the purpose of control of the inverter by decoupling control and PI control is achieved. From the point of energy on direct power control system, the active, inactive power of output AC of inverter are calculated ,and suitable space voltage vector was selected after comparing with the given values to realize the direct control of the power set point. The basic theory of two control strategies and implementation method are included, and the simulation model was established based on MATLAB/Simulink. And their simulation results, characteristics of two kinds of control methods were compared through simulation data analysis. On the basic of results, the direct power control is better than the double closed loop control.

Realization of Fixed Switching Frequency Direct Power Control for Three-Phase AC/DC Converter

2013 ◽  
Vol 385-386 ◽  
pp. 1216-1219
Author(s):  
Yun Liang Wang ◽  
Yong Le Zhao
Keyword(s):  
Power Control ◽  
Pulse Width Modulation ◽  
Control Strategies ◽  
Modulation Method ◽  
Switching Frequency ◽  
Direct Power ◽  
Direct Power Control ◽  
Three Phase ◽  
Simulation Results ◽  
Virtual Flux

This paper presents fixed switching frequency direct power control (FSF-DPC) for three-phase AC/DC converter. Sensorless control strategies based on virtual-flux can optimize the performance of the system. In this paper, realization of pulse width modulation method for FSF-DPC is presented. The simulation results show that the system running performance is good.

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.

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