DOI: https://doi.org/10.20535/kpi-sn.2019.3.176055

CONTROL ALGORITHM OF TWO-CHANNEL FUZZY CONTROLLER FOR HEAT-ENERGY OBJECTS

Yuriy M. Kovrygo, Pavlo V. Novikov

Abstract


Background. The reasons of control systems poor operation of complex heat and power control objects operating in changeable modes are analyzed. The peculiarity of the direct-flow steam boiler as a control object is the limited ability to conduct experimental research for identification. The incompleteness of the mathematical description does not allow fully formalizing the object for reliable design of automation systems. The temperature control circuits of the direct-flow boiler are characterized by high accumulation capacity, time delay, nonlinearity of dynamic characteristics, mutual influence of control circuits, which makes it actual to develop new control algorithms to improve the efficiency of existing control systems.

Objective. The purpose is to obtain an algorithm of the control system that is insensitive to the uncertainty of the object parameters, that considers the presence of time delay through reference and disturbance channels and guarantees the given quality of regulation in changeable modes.

Methods. Peculiarities of dynamic characteristics of multicapacity objects with time delays are considered. A new approach to the synthesis of fuzzy control systems is described, which addrress the adverse properties of thermal power objects, based on the experience of the operation of these facilities. Computer simulation of the synthesized control system was carried out.

Results. Computer modeling confirms the rightfulness and feasibility of the proposed control algorithm. The two-channel structure of the fuzz-controller allows implementing a control method close to optimal in manual control by an experienced operator.

Conclusions. With the availability of two parallel channels, the tasks for providing given quality of control system and its stability margin are delimited. The described structure of a two-channel fuzz-controller can be used to minimize the dynamic error in the initial stage of the transition process and reduce the oscillation at the final stage.

Keywords


Fuzzy logic; Nonstationarity; Delay; Transport delay; Stability margin; Control system

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