scholarly journals Research on Discretization PI Control Technology of Single-Phase Grid-Connected Inverter with LCL Filter

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Jianke Li ◽  
Jinquan Wang ◽  
Ye Xu ◽  
Jianting Li ◽  
Jingjing Chen ◽  
...  
Keyword(s):  
Dynamic Performance ◽  
Numerical Algorithms ◽  
Switching Frequency ◽  
Lcl Filter ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Loop Control System ◽  
Grid Connected Inverter ◽  
The Stability ◽  
The Cost

Compared with L-type filter, LCL-type filter is more suitable for high-power low-switching frequency applications with reducing the inductance, improving dynamic performance. However, the parameter design for the LCL filter is more complex due to the influence of the controller response performance of the converter. If the harmonic current around switching frequency can be fully suppressed, it is possible for inverter to decrease the total inductance as well as the size and the cost. In this paper, the model of the LCL filter is analyzed and numerical algorithms are adopted to analyze the stability of the closed-loop control system and stable regions are deduced with different parameters of LCL filter. Then, the minimum sampling frequencies are deduced with different conditions. Simulation and experimental results are provided to validate the research on the generating mechanism for the unstable region of sampling frequency.

scholarly journals A NOVEL METHOD FOR DESIGNING THE CONTROLLER OF A LCL-FILTER-BASED GRID-CONNECTED INVERTER WITH CONSIDERING VARYING SYSTEM PARAMETERS

2018 ◽  
Vol 54 (3A) ◽  
pp. 39
Author(s):  
Nguyen Trung Nhan
Keyword(s):  
Controller Design ◽  
Design Method ◽  
Lcl Filter ◽  
Loop Control ◽  
System Parameters ◽  
Three Phase ◽  
Loop Control System ◽  
Novel Method ◽  
Grid Connected Inverter ◽  
The Stability

Exactly determining the control coefficients for the controller of a three-phase LCL-filter-based inverter is an important and challenging issue in microgrid systems. However, existing LCL-filter-based inverter systems usually assume that all system parameters are determined accurately and remain constant over time, which is not true in real situations. Variations in the system parameters are known to possibly seriously degrade the performance of LCL-filter-based inverter systems. For efficiency and robustness, this paper proposes a novel method for the generalized controller design of a three-phase LCL-filter-based grid-connected inverter system that can address deviations in system parameters. An optimum way to determine the stability bounds under various system parameters cases is introduced. The assessment of the stability bounds is based on the Routh criterion by solving the characteristic equation of the closed-loop control system. Simulations results are presented to validate the correctness and effectiveness of the proposed design method.

Study on Twin-Rotary Motion Control System Based on Siemens Technology CPU

2012 ◽  
Vol 229-231 ◽  
pp. 2201-2204
Author(s):  
Cun Hai Pan ◽  
Hui Li ◽  
Su Mei Du ◽  
Wei Gao
Keyword(s):  
Control System ◽  
Motion Control ◽  
Rotary Motion ◽  
Three Dimension ◽  
Motion Control System ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Loop Control System ◽  
Dimension Space ◽  
The Cost

A twin-rotary motion control system was built based on a cam technology and Siemens S7-300T PLC in this paper. The system can position accurately in a three-dimension space using a twin-servo closed loop control system and can real-time monitor various parameters of positioning system by HMI (Human Machine Interface). It also can automatically collect various parameter information and judge the type of fault.At the same time, the degree of automation has been raised and the cost of production was reduced.

Research on INS-Aided GNSS Carrier Tracking Loop in High Dynamic Circumstance

2013 ◽  
Vol 464 ◽  
pp. 215-221
Author(s):  
Xin Long Wang ◽  
Chuan Jun Li ◽  
Xing Cheng Li
Keyword(s):  
Dynamic Environment ◽  
Coupled System ◽  
Tracking Performance ◽  
Tracking Loop ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Loop Control System ◽  
Tightly Coupled ◽  
High Dynamic ◽  
The Stability

GNSS receiver will produce a large Doppler shift in high dynamic environment, thus causing lock-lose of the tracking loop. INS-aided GNSS tightly coupled system can improve tracking performance in high dynamic environment by introducing the Doppler information estimated by INS. Through analyzing by the theory of closed loop control system theory and numerical simulation of the INS-aided carrier tracking loop, the results show that INS-aided carrier tracking loop can obviously improve the stability of carrier tracking performance and anti-jamming ability of the satellite navigation receiver in high dynamic circumstance.

Separated-PI Control Strategy and Stability Analysis of a Single-Phase Inverter Connected to the Grid with a LCL Filter

2013 ◽  
Vol 291-294 ◽  
pp. 2464-2469
Author(s):  
Dian Li Hou ◽  
Qing Fan Zhang ◽  
Xiao Liu
Keyword(s):  
Control Strategy ◽  
Single Phase ◽  
Dynamic Performance ◽  
Structural Features ◽  
Lcl Filter ◽  
Phase Inverter ◽  
Hurwitz Stability ◽  
Single Phase Inverter ◽  
Grid Connected Inverter ◽  
The Stability

Because of the powerful filtering ability the third-order LCL filters has been widely used in grid-connected inverters, but there are some problems to be solved on systems stability and control accuracy. A separated-PID control strategy has been proposed according to the PID characteristics and the structural features of a single-phase inverter connected to the grid with a LCL filter. This control strategy has some advantages as a strong dynamic tacking stability, and the system output has a small steady state error. A detailed description is presented on this control strategy applied in the single-phase grid inverter with a LCL filter. According to the Routh-Hurwitz stability criterion, the stability of a grid-connected inverter system based on the proposed control strategy has been analyzed. Finally, waveforms of this inverter have been presented through a simulation to show the steady and dynamic performance of the proposed scheme.

The Direct Torque Control Research of Permanent Magnet Linear Synchronous Motor

2011 ◽  
Vol 143-144 ◽  
pp. 350-354
Author(s):  
Jun Zhu ◽  
Xu Dong Wang ◽  
Bao Yu Xu ◽  
Hai Chao Feng
Keyword(s):  
Simulation Experiment ◽  
Control Method ◽  
Dynamic Performance ◽  
Direct Torque Control ◽  
Torque Control ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Hysteresis Controller ◽  
Control Research ◽  
Loop Control System

In order to improve the dynamic servo performance of PMLSM, a classical direct torque control (DTC) scheme based on bang-bang control is proposed in the paper. The proposed control method uses the bang-bang hysteresis controller formed a dual-closed loop control system, it contains torque loop and flux loop. The DTC control model was established and the simulation experiment was made. The simulation experiment results show that the DTC can improve the dynamic performance of PMLSM. It can reduce the ripples of speed and torque, so that it can provide more precision and accuracy servo performance.

The role of walking surface in enhancing the stability of the simplest passive dynamic biped

Robotica ◽  
2014 ◽  
Vol 33 (1) ◽  
pp. 195-207 ◽  
Author(s):  
Ali Tehrani Safa ◽  
Mahyar Naraghi
Keyword(s):  
Gait Stability ◽  
Loop Control ◽  
Contact Points ◽  
Closed Loop Control System ◽  
Bipedal Gait ◽  
Loop Control System ◽  
The Stability ◽  
Straight Lines ◽  
Inclined Surface

SUMMARYEmploying passive dynamics of the simplest point-foot walker, we have shown that the walking surface could have a great role in promoting the gait stability. In this regard, the stabilization of the simplest walking model,3 between the range of slopes greater than 0.0151 rad. and less than 0.26 rad., has been achieved. The walker like other passive dynamic walking models has no open or closed-loop control system; so, is only actuated by the gravity field. Moreover, no damper or spring is used. Obviously, according to the model's unstable behavior, it is unable to walk on an even flat ramp between the mentioned intervals.3 Here, instead of restraining the model, we let it explore other smooth surfaces, walking on which, will end in an equally inclined surface. To reach the objective, we employ a parallel series of fixed straight lines (local slopes) passing through contact points of an unstable cycling gait, which is generated by an ordinary ramp. To categorize, we have nicknamed those local slopes that guide the biped to a stable cyclic walking, “Ground Attractors,” and the other, leading it to a fall, “Repulsive Directions.” Our results reveal that for the slope <0.26 rad., a closed interval of ground attractors could be found. Stabilization of those unstable limit cycles by this technique makes obvious the key role of walking surface on bipedal gait. Furthermore, following our previous work,13 the results confirm that the two thoroughly similar walking trajectories can have different stability. All of these results strongly demonstrate that without considering the effects of a walking surface, we cannot establish any explicit relationship between the walker's speed and its stability.

Application of Back-to-Back Circuit in the Intelligent Wheelchair Charging Technology

2014 ◽  
Vol 631-632 ◽  
pp. 654-659
Author(s):  
Li Wang ◽  
Rong Yang ◽  
Xiu Feng Zhang ◽  
Yan Ma
Keyword(s):  
Design Method ◽  
Voltage Source ◽  
Super Capacitor ◽  
Loop Control ◽  
Intelligent Wheelchair ◽  
Closed Loop Control System ◽  
Loop Control System ◽  
Pwm Rectifiers ◽  
Bus Voltage ◽  
The Stability

Intelligent wheelchair charging technology put forward a very high request to the stability of the DC bus voltage. This paper describes the three phase principles and topology with Back-to-Back, SVPWM is used to the voltage-source PWM rectifiers, the principle of voltage and current double closed loop control system design the system. According to the principle of super-capacitor store energy for the load and construct their simulation model with SIMULINK. Simulation results demonstrate the feasibility of the above design method.

Research on Control Strategy for the Three-Phase Grid-Connected Inverter

2012 ◽  
Vol 614-615 ◽  
pp. 1578-1582
Author(s):  
Chun Qing Qi ◽  
Yi Ruan ◽  
Feng Wen Cao
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Response Speed ◽  
Current Control ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Three Phase ◽  
Control Scheme ◽  
Loop Control System ◽  
Grid Connected Inverter

This paper proposes a control strategy，based on the grid voltage oriented vector control (VOC), which makes three-phase inverter control the active and reactive power of grid-connected inverter under the premise of the direct current control. This paper analyzes the principle of three phase photovoltaic grid connected inverter and describes the control structure of the inverter. The control strategy can overcome the deficiencies of the indirect current control scheme. This paper designs the current closed-loop control system, which not only improve the system dynamic response speed and output current waveform quality, while also reduce its sensitivity to parameter changes to improve the robustness of the system. The simulation results show the validity of control strategy proposed.

The Development of the Closed-Loop Control System for the Mechanical Suspensions Test Rig

2013 ◽  
Vol 655-657 ◽  
pp. 1361-1364
Author(s):  
Yan Liu
Keyword(s):  
Control System ◽  
Closed Loop ◽  
Performance Test ◽  
Closed Loop Control ◽  
Test Rig ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Loop Control System ◽  
Mechanical Suspension ◽  
The Cost

Frequency and amplitude of the existing mechanical suspension performance test rig can not change. And it has signal function. Frequency changing devices and amplitude adjustment mechanism were designed on it by study. Frequency and amplitude of the improved test rig can change within a certain range. It has two control algorithms: fixed-frequency vibration and sweep vibration. And the used closed-loop control in the system ensures the reliability of the system. The results show feasibility and correctness of this control system by a large number of experiments. It improves the function of the test rig and decreases the cost of study.

New approach to control of robotic manipulators interacting with dynamic environment

Robotica ◽  
1996 ◽  
Vol 14 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Miomir K. Vukobratović ◽  
Yuri Ekalo
Keyword(s):  
Dynamic Environment ◽  
Interaction Force ◽  
Robot Motion ◽  
Control Procedure ◽  
Control Laws ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Control Concept ◽  
Loop Control System ◽  
The Stability

SummaryThe fundamentals of an approach to solving the control task of robots interaction with a dynamic environment based on the stability of a closed-loop control system are given in this paper. The task is set and solved in its general form. The traditional control concept of compliant robot motion—the hybrid position/force control is discussed. In the paper the proposed control laws ensure simultaneous stabilization of both the desired robot motion and the desired interaction force, as well as their required quality of transient responses. In order to emphasize the fundamental point of this approach in controlling the contact tasks in robotics, the authors have assumed ideal parameters of interacting dynamic systems. The proposed control procedure is demonstrated by one simple example.

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