FUZZY CONTROLLER FOR MEDIUM-SCALE BIOMASS BOILER

The combustion in biomass boilers is classified as a non-homogeneous combustion process. This phenomenon is known as difficulty controllable by common control algorithms due to its inappropriate properties e.g. non-linear static characteristics, limitation of control variable quantity, transitions with a time delay or even behavior similar to non-minimal phase systems. Due to these properties the usage of traditional linear controllers leads to unsatisfactory results. The authors decided to use fuzzy controller with behavior similar to PID controller but with adaptation to most problematic properties of combustion process. The results were experimentally verified on a 100 kW biomass combustion boiler

Využití filtrů typu dolní propust při spalování biomasy

Quantities measured during biomass combustion experiments are heavily burdened with a considerable noise. Usage of common linear low-pass filters is able to smooth measured time rows but it also introduces typical dynamic delay of filtered data. The article presents comparison of three commonly used linear filters – Butterworth, Bessel and Chebishev. An effort to smooth measured data without introducing dynamic delay led us to use some of less common non-linear filters. The article further presents usage of Threshold and Gaussian weighted average non-linear filters and compares them with the linear ones.Veličiny sledované při experimentech se spalováním biomasy jsou zpravidla významně zatížené silným šumem. Použití běžných lineárních filtrů s dolní propustí sice dokáže vyhladit průběhy měřených veličin, ale zavádí do filtrovaného signálu typické dynamické zpoždění. Tento článek porovnává použití tří běžně používaných lineární filtrů - Butterworthův, Besselův a Čebiševův. Další snaha o vyhlazení měřených dat bez zatížení dynamickým zpožděním vedla autory k použití méně běžných nelineárních filtrů. Článek tedy dále srovnává použití prahového filtru a filtru založeném na Gaussovo křivkou váženém průměru

Optimal Combustion Conditions for a Small-scale Biomass Boiler

This paper reports on an attempt to achieve maximum efficiency and lowest possible emissions for a small-scale biomass boiler. This aim can be attained only by changing the control algorithm of the boiler, and in this way not raising the acquisition costs for the boiler. This paper describes the experimental facility, the problems that arose while establishing the facility, and how we have dealt with them. The focus is on discontinuities arising after periodic grate sweeping, and on finding the parameters of the PID control loops. Alongside these methods, which need a lambda probe signal for proper functionality, we inroduce another method, which is able to intercept the optimal combustion working point without the need to use a lambda sensor