Improved frequency response model identification method for processes with initial cyclic-steady-state

AIChE Journal ◽  
2011 ◽  
Vol 57 (12) ◽  
pp. 3429-3435 ◽  
Author(s):  
Yu Jin Cheon ◽  
Su Whan Sung ◽  
Jietae Lee ◽  
Cheol Ho Je ◽  
In-Beum Lee
Keyword(s):  
Steady State ◽  
Frequency Response ◽  
Model Identification ◽  
Response Model ◽  
Identification Method

scholarly journals Black-Box Behavioral Modeling of Voltage and Frequency Response Characteristic for Islanded Microgrid

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2049 ◽  
Author(s):  
Yong Shi ◽  
Dong Xu ◽  
Jianhui Su ◽  
Ning Liu ◽  
Hongru Yu ◽  
...  
Keyword(s):  
Frequency Response ◽  
Least Squares Method ◽  
Model Identification ◽  
Response Characteristic ◽  
Black Box ◽  
System Stability ◽  
Model Parameters ◽  
Response Model ◽  
Modeling Process ◽  
Damped Least Squares

The voltage and frequency response model of microgrid is significant for its application in the design of secondary voltage frequency controller and system stability analysis. However, most models developed for this aspect are complex in structure due to the difficult mechanism modeling process and are only suitable for offline identification. To solve these problems, this paper proposes a black-box modeling method to identify the voltage and frequency response model of microgrid online. Firstly, the microgrid system is set as a two-input, two-output black-box system and can be modeled only by data sampled at the input and output ports. Therefore, the simplicity of modeling steps can be guaranteed. Meanwhile, the recursive damped least squares method is used to realize the online model identification of the microgrid system, so that the model parameters can be adjusted with the change of the microgrid operating structure, which makes the model more adaptable. The paper analyzes the black-box modeling process of the microgrid system in detail, and the microgrid platform, including 100 kW rated power inverters, is employed to validate the analysis and experimental results.

A frequency response identification method for discrete-time processes with cyclic steady state conditions

Automatica ◽  
2014 ◽  
Vol 50 (12) ◽  
pp. 3260-3267 ◽  
Author(s):  
Kyungsu Kim ◽  
Yu Jin Cheon ◽  
In-Beum Lee ◽  
Jietae Lee ◽  
Su Whan Sung
Keyword(s):  
Steady State ◽  
Frequency Response ◽  
Discrete Time ◽  
Identification Method

Discrete-time frequency response identification method for processes with final cyclic-steady-state

2014 ◽  
Vol 24 (6) ◽  
pp. 1002-1014 ◽  
Author(s):  
Kyung Hwan Ryu ◽  
Si Nae Lee ◽  
Chang-Mo Nam ◽  
Jietae Lee ◽  
Su Whan Sung
Keyword(s):  
Steady State ◽  
Frequency Response ◽  
Discrete Time ◽  
Time Frequency ◽  
Identification Method

Iterative feedback control based on frequency response model for a six-degree-of-freedom micro-vibration platform

2021 ◽  
pp. 107754632199731
Author(s):  
He Zhu ◽  
Shuai He ◽  
Zhenbang Xu ◽  
XiaoMing Wang ◽  
Chao Qin ◽  
...  
Keyword(s):  
Feedback Control ◽  
Frequency Response ◽  
Control Strategy ◽  
Degree Of Freedom ◽  
Small Displacement ◽  
Response Model ◽  
Parameter Uncertainties ◽  
Micro Vibration ◽  
Six Degree Of Freedom ◽  
Iterative Feedback

In this article, a six-degree-of-freedom (6-DOF) micro-vibration platform (6-MVP) based on the Gough–Stewart configuration is designed to reproduce the 6-DOF micro-vibration that occurs at the installation surfaces of sensitive space-based instruments such as large space optical loads and laser communications equipment. The platform’s dynamic model is simplified because of the small displacement characteristics of micro-vibrations. By considering the multifrequency line spectrum characteristics of micro-vibrations and the parameter uncertainties, an iterative feedback control strategy based on a frequency response model is designed, and the effectiveness of the proposed control strategy is verified by performing integrated simulations. Finally, micro-vibration experiments are performed with a 10 kg load on the platform. The results of these micro-vibration experiments show that after several iterations, the amplitude control errors are less than 3% and the phase control errors are less than 1°. The control strategy presented in this article offers the advantages of a simple algorithm and high precision and it can also be used to control other similar micro-vibration platforms.

Nonlinear filter properties of the thick ascending limb

1997 ◽  
Vol 273 (4) ◽  
pp. F625-F634 ◽  
Author(s):  
H. E. Layton ◽  
E. Bruce Pitman ◽  
Leon C. Moore
Keyword(s):  
Steady State ◽  
Frequency Response ◽  
Transit Time ◽  
Concentration Profile ◽  
Tubuloglomerular Feedback ◽  
Thick Ascending Limb ◽  
Transport Parameters ◽  
Nodal Structure ◽  
Nacl Concentration ◽  
Fluid Transit Time

A mathematical model was used to investigate the filter properties of the thick ascending limb (TAL), that is, the response of TAL luminal NaCl concentration to oscillations in tubular fluid flow. For the special case of no transtubular NaCl backleak and for spatially homogeneous transport parameters, the model predicts that NaCl concentration in intratubular fluid at each location along the TAL depends only on the fluid transit time up the TAL to that location. This exact mathematical result has four important consequences: 1) when a sinusoidal component is added to steady-state TAL flow, the NaCl concentration at the macula densa (MD) undergoes oscillations that are bounded by a range interval envelope with magnitude that decreases as a function of oscillatory frequency; 2) the frequency response within the range envelope exhibits nodes at those frequencies where the oscillatory flow has a transit time to the MD that equals the steady-state fluid transit time (this nodal structure arises from the establishment of standing waves in luminal concentration, relative to the steady-state concentration profile, along the length of the TAL); 3) for any dynamically changing but positive TAL flow rate, the luminal TAL NaCl concentration profile along the TAL decreases monotonically as a function of TAL length; and 4) sinusoidal oscillations in TAL flow, except at nodal frequencies, result in nonsinusoidal oscillations in NaCl concentration at the MD. Numerical calculations that include NaCl backleak exhibit solutions with these same four properties. For parameters in the physiological range, the first few nodes in the frequency response curve are separated by antinodes of significant amplitude, and the nodes arise at frequencies well below the frequency of respiration in rat. Therefore, the nodal structure and nonsinusoidal oscillations should be detectable in experiments, and they may influence the dynamic behavior of the tubuloglomerular feedback system.

A low-order system frequency response model

1990 ◽  
Vol 5 (3) ◽  
pp. 720-729 ◽  
Author(s):  
P.M. Anderson ◽  
M. Mirheydar
Keyword(s):  
Frequency Response ◽  
Order System ◽  
Response Model ◽  
System Frequency ◽  
Low Order
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