I am simulating a DC micro grid with different control techniques (PI, SMC Fuzzy logic). The results of Fuzzy logic is better in the beginning. Is it possible the Fuzzy logic control technique gives the better response than the PI and SMC based control? please look the figure and comment.
THANKS
Try to reduce the overshoot in case of fuzzy, also work on constants in SMC and compare the response...
Dear Kashif Mehmood
PI (proportional-integrative) control is one of the best known control techniques in industry. However, it is a linear controller and for nonlinear systems it would be incapacitated. Moreover, SMC (sliding mode control), although is widely carried out in theoretical research, whereas, it is less practical for implementation in real physical systems, due to its discontinuous nature, along with some deficiencies as state chatter which naturally results in control chatter. Meanwhile, Fuzzy Logic controller is based on degree of truth, hence it is out of computer Boolean logic which is (1 or 0). Therefore, simply we cannot expect a computer processor to conveniently work with Fuzzy Logic, it means to program a computer with Fuzzy Logic is bothersome. Since, any controller is similar to a computer processor, thus Fuzzy Logic is not swiftly implemented as a computer code in the controller embedded system, and it is troublesome also through the scope of electronic circuitry design.
Regarding this discussion, in my opinion, I think for a linear system PI is the best known controller, while for nonlinear systems there are some alternatives as SMC, CLF (control-Lyapunov function), and numerical methods as optimal control. Moreover, this categorization is independent of your problem at hand, the so-called "DC micro-grid" control problem.
Fuzzy logic is an approach to computing based on "degrees of truth" rather than the usual "true or false" (1 or 0) Boolean logic on which the modern computer is based.
Please see: https://searchenterpriseai.techtarget.com/definition/fuzzy-logic#:~:text=Fuzzy%20logic%20is%20an%20approach,at%20Berkeley%20in%20the%201960s.
Please also see:
https://www.researchgate.net/post/What_are_the_drawbacks_of_Sliding_Mode_Observer_SMO
Hi Kashif Mehmood
Yes, it can, depending on your control performance requirements. You may want to run the system a little longer and check the performance index of each controller in order to compare them fairly.
The are few types of fuzzy control schemes. What exactly is your fuzzy logic controller?
Your SMC is rather sluggish, so I guess it is not the conventional SMC, u = – k·sign(s).
I see the results obtained for the voltage control show a good stable transient for different controllers.
The fuzzy controller can improve the control law in transient state,
it helps to achieve faster dynamique with a short rise time and response time compared to other controllers, which makes better controller
I think yes. Because in fuzzy logic control you can define controller based on human logic. Furthermore, in sliding mode there are an sliding surface based on formula, for example step function or arctan function. In fuzzy control you can define any arbitrary surface and function. In other word, Fuzzy control is more comprehensive than Sliding mode control and it includes sliding mode control.
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