IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308 _______________________________________________________________________________________ Volume: 04 Issue: 04 | Apr-2015, Available @ http://www.ijret.org 176 PARAMETER CONTROLLING OF BOILER IN POWER PLANTS USING FUZZY LOGIC CONTROLLER Santanu Das 1 , Sridhar Raja 2 1 M-tech Student, Department of Electronics and Instrumentation, Bharath University, Chennai, India 2 Assistant professor, Department of Electronics and Instrumentation, Bharath University, Chennai, India Abstract Boilers are used industrially both for electric power generation and for supplying process stream in thermal power plants and its control is very important in many field applications. In some situation conventional PID control technique is being used for control purpose. These conventional controllers are not well suitable for some unusual conditions like load disturbances. Fuzzy logic control technique is being used to overcome these problems. A closed loop control system incorporating fuzzy logic has been developed for a class of industrial control systems. A unique fuzzy logic controller (FLC) structured with an efficient realization and a small rule base that can be easily implemented in existing industrial controllers. Fuzzy logic control system is much closer to human thinking and natural language than traditional control systems. This paper describes a fuzzy control technique and its implementation in boiler controls. Here a PIC microcontroller is being used where fuzzy control algorithm is implemented. Keywords: Fuzzy logic control, fuzzy logic controller, boiler controls, PIC microcontroller --------------------------------------------------------------------***------------------------------------------------------------------ 1. INTRODUCTION Temperature is a vital parameter in boiler because it produces process stream. Temperature variation plays a negative impact in sophisticated instrument in hardware industries as well as it shows an importance in commercial applications. An uncertain temperature difference may cause various difficulties and can damage various instruments that are in use in particular system, so it is very necessary to take a desire step to solve the problem automatically. In conventional PID controller it is very difficult to get P,I,D coefficients and it has less system stability with high rise time, high peak overshoot in unusual conditions. PID control may not even be needed in very slow process, like home heating control systems. Introduced in the earlier 1970s, fuzzy systems and fuzzy control theories as an emerging technology targeting industrial applications have added a promising new dimension to the existing domain of conventional control systems engineering. . It is now a common belief that when a complex physical system does not provide a set of differential or difference equations as a precise or reasonably accurate mathematical model, particularly when the system description requires certain human experience in linguistic terms, fuzzy systems and fuzzy control theories have some salient features and distinguishing merits over many other approaches. Fuzzy logic is conceptually easy to understand. The mathematical concept behind fuzzy reasoning is very simple and flexible in any given system. Fuzzy logic is tolerant of imprecise data. Everything is imprecise if you look closely, but more than that, most things are imprecise even on careful inspection. Fuzzy logic can model nonlinear functions of arbitrary complexity. We can create a fuzzy system to match any set of input-output data. Fig.1. Block diagram of the system 2. PROPOSED METHODOLOGY Boiler temperature and level are monitored and controlled in this system. We have to program the microcontroller according to our objective by using fuzzy logic process. The temperature sensor continuously monitors the temperature and sends it to the microcontroller. Temperature is set through the keypad which is interfaced with microcontroller. This set value is compared with the current temperature. Microcontroller provides different control output for maintaining the temperature level to set the level through the fuzzy logic process. This control output is given to the DAC which moves TRAIC circuit voltage to the heater according to temperature sensor feedback. This process can maintain a temperature level to the required level.