Two examples of simple switching control overcoming the performance limitation of linear feedback

Author(s):  
Bo Zhu ◽  
Shuguo Liang
Author(s):  
Bo Zhu ◽  
Kai-Yuan Cai

In the paper, we show that for a class of linear plants, although the common linear control can be used to stabilize them, the step responses of the resulting closed-loop systems must have overshoot; however, a simple switching between them may avoid the overshoot. This indicates that switching control may overcome the performance limitation of linear feedback control in the overshoot-avoidance respect. A simple switching control scheme with such a quality is exploited and the conditions for its existence are presented. In the scheme, two common controllers are needed and they are only required to guarantee no overshoot on the time intervals [0, ts) and [ts, ∞), respectively, where ts denotes the switching time. For actual implementation, a state-dependent version of the switching control law is developed. Two examples are presented to show its effectiveness.


Author(s):  
A. Suresh Babu ◽  
B. Anand

: A Linear Feedback Shift Register (LFSR) considers a linear function typically an XOR operation of the previous state as an input to the current state. This paper describes in detail the recent Wireless Communication Systems (WCS) and techniques related to LFSR. Cryptographic methods and reconfigurable computing are two different applications used in the proposed shift register with improved speed and decreased power consumption. Comparing with the existing individual applications, the proposed shift register obtained >15 to <=45% of decreased power consumption with 30% of reduced coverage area. Hence this proposed low power high speed LFSR design suits for various low power high speed applications, for example wireless communication. The entire design architecture is simulated and verified in VHDL language. To synthesis a standard cell library of 0.7um CMOS is used. A custom design tool has been developed for measuring the power. From the results, it is obtained that the cryptographic efficiency is improved regarding time and complexity comparing with the existing algorithms. Hence, the proposed LFSR architecture can be used for any wireless applications due to parallel processing, multiple access and cryptographic methods.


Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3083
Author(s):  
Mohamed Amine Fnaiech ◽  
Jaroslaw Guzinski ◽  
Mohamed Trabelsi ◽  
Abdellah Kouzou ◽  
Mohamed Benbouzid ◽  
...  

This paper presents a newly designed switching linear feedback structure of sliding mode control (SLF-SMC) plugged with an model reference adaptive system (MRAS) based sensorless field-oriented control (SFOC) for induction motor (IM). Indeed, the performance of the MRAS depends mainly on the operating point and the parametric variation of the IM. Hence, the sliding mode control (SMC) could be considered a good control alternative due to its easy implementation and robustness. Simulation and experimentation results are presented to show the superiority of the proposed SLF-SMC technique in comparison with the classical PI controller under different speed ranges and inertia conditions.


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