Noise-sensitive feedback loop identification in linear time-varying analog circuits

2017 ◽  
Author(s):  
Ang Li ◽  
Peng Li ◽  
Tingwen Huang ◽  
Edgar Sanchez-Sinencio
Keyword(s):  
Analog Circuits ◽  
Feedback Loop ◽  
Linear Time ◽  
Time Varying

Study on Control System of Turbine Speed of 600MW Ultra-Supercritical Unit

2012 ◽  
Vol 516-517 ◽  
pp. 660-664
Author(s):  
Da Ye Ding ◽  
Shao Juan Yu ◽  
Chen Li
Keyword(s):  
Control System ◽  
Feedback Loop ◽  
Linear Time ◽  
Stability Control ◽  
Energy Utilization ◽  
Time Varying ◽  
Loop Control ◽  
Fast Tracking ◽  
Loop Control System ◽  
Turbine Speed

The development of ultra-supercritical units is feasible choice of energy utilization ratio in China, its stability and economy rely on control system of turbine mightily. The control system of 600MW turbine is widely used currently, according to the non-linear time-varying excitation control system of turbine speed, the speed of turbine is employed as the feedback variable, a controller combined with a PID feedback loop control system is designed, analyzed and studied respectively from theory and emulation. The simulation results shows that PID feedback control has good effects in inhibiting interference andstabilizing system. Put forward strategy that can control the speed of turbine on this basis in order to achieve the goal of turbine’s fast tracking and stability control.

scholarly journals The VIT Transform Approach to Discrete-Time Signals and Linear Time-Varying Systems

Eng ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 99-125
Author(s):  
Edward W. Kamen
Keyword(s):  
Discrete Time ◽  
Initial Conditions ◽  
Linear Time ◽  
Order Term ◽  
Initial Time ◽  
Time Varying ◽  
Varying Coefficients ◽  
Time Signals ◽  
Time Varying Systems ◽  
Time Varying Coefficients

A transform approach based on a variable initial time (VIT) formulation is developed for discrete-time signals and linear time-varying discrete-time systems or digital filters. The VIT transform is a formal power series in z−1, which converts functions given by linear time-varying difference equations into left polynomial fractions with variable coefficients, and with initial conditions incorporated into the framework. It is shown that the transform satisfies a number of properties that are analogous to those of the ordinary z-transform, and that it is possible to do scaling of z−i by time functions, which results in left-fraction forms for the transform of a large class of functions including sinusoids with general time-varying amplitudes and frequencies. Using the extended right Euclidean algorithm in a skew polynomial ring with time-varying coefficients, it is shown that a sum of left polynomial fractions can be written as a single fraction, which results in linear time-varying recursions for the inverse transform of the combined fraction. The extraction of a first-order term from a given polynomial fraction is carried out in terms of the evaluation of zi at time functions. In the application to linear time-varying systems, it is proved that the VIT transform of the system output is equal to the product of the VIT transform of the input and the VIT transform of the unit-pulse response function. For systems given by a time-varying moving average or an autoregressive model, the transform framework is used to determine the steady-state output response resulting from various signal inputs such as the step and cosine functions.

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