автоматика
M. Хаджийски, Н. Делийски, Д. Ангелски, П. Вичев, К. Атанасова, Изчисляване на енергийния разход и компонентите му за пластифициране на съдържащи лед трупи в производството на фурнир

Статията е 1 от 9 в списание АВТОМАТИКА И ИНФОРМАТИКА 2, 2024 г.

Key Words: Logs; frozen bound water; frozen free water; thermal treatment; plasticizing; energy consumption; veneer production.

Abstract. An approach for computing the energy required for warming up and plasticizing of frozen logs subjected to thermal treatment in the production of veneer has been presented. The approach is based on the use of two personal models. With the help of the non-stationary model, the thermal treatment times of beech logs with a diameter of 0.4 m, initial temperatures of –1 °C, –10 °C, –20 °C, –30 °C and moisture content u of 0.4 kg∙kg-1, 0.6 kg∙kg-1, and 0.8 kg∙kg-1 were determined at operating temperatures in the boiling or steaming equipment equal to 80 °C. For different combination of the three values of moisture content and four values of the initial log temperature there are significant differences between the amount of both free and bound frozen water in the logs, which ensures sufficiently large differences between the calculated values of the energy consumption of the logs. Furthermore, the logs with initial temperature of –1 °C contain only frozen free water and no frozen bound water at all. Using the determined logs’ thermal treatment durations, with the help of our second model the change in the energy required for warming up and plasticizing of the investigated logs and that for each of its 4 components was calculated. It was found that the studied energy increases from 55.3 to 67.2 kWh∙m-3 at u = 0.4 kg∙kg-1, from 75.9 to 89.1 kWh∙m-3 at u = 0.6 kg∙kg-1 and from 94.6 to 108.8 kWh∙m-3 at u = 0.8 kg∙kg-1 when the initial temperature of the logs decreases from –10 °C to –30 °C. At initial log temperature of –1 °C the energy required for plastcizing of the wood changes from 46.0 kWh∙m-3 at u = 0.4 kg∙kg-1 to 84.9 kWh∙m-3 at u = 0.8 kg∙kg-1. Four types of individual components of the considered energy have been calculated, namely: for warming um of the frozen and non-frozen wood itself, for melting of the temperature dependent frozen part of bound water, and for melting all
frozen free water in the logs.

Повече

автоматика
Н. Н. Николов, Управление на едномерни обекти с голямо закъснение чрез дискретни регулатори на състоянието

Статията е 2 от 9 в списание АВТОМАТИКА И ИНФОРМАТИКА 2, 2024 г.

Key Words: Discrete state controller; objects with a delay; state observer; Smith predictor systemр Pade series.

Abstract. The control is a purposeful impact on the object of control, as a result of which it is brought to a desired state, which is determined by the requirements of the technological process. The main requirement is that this process is sustainable, but this is not enough. There are also certain requirements regarding the quality of the processes that take place in the system – quick action when working out disturbing effects or when changing the mode of operation, permissible deviations from the established mode, amplitude limitations of the controlling effects, etc. Often the requirements for the managed process are mutually contradictory and it is necessary to seek a reasonable compromise between them. It is accepted, when the feedback in a control system is carried out by means of the state vector, the controller in this system is called a State Controller (SC). If the state x(k) can be measured directly at every moment k=0, 1, 2, … we speak of control in the presence of complete information. When the state cannot be measured directly, but is estimated by other quantities that are related to it and available for measurement, it is said to be control with incomplete information. The delay in the object of control, whatever its nature, its presence creates difficulties in the implementation of the control system, worsening the quality indicators of the ongoing processes. When using a discrete state controller to control objects with a delay, in order to be able to synthesize the state observer it is necessary to represent the delay unit with a fractional-rational function using a Pade series. This enables the object of control to be represented as a higher-order object without delay, but leads to a significant extension of the transition process in the system.

Повече

автоматика
Г. Костов, Р. Александров, Определяне на електромагнитния момент на превключваем реактивен двигател

Статията е 3 от 9 в списание АВТОМАТИКА И ИНФОРМАТИКА 2, 2024 г.

Key Words: Switched Reluctance Motor; rotor position; motor torque; co-energy; JMAG-Express software.

Abstract. Due to the development of electronics and control methods, interest in Switched Reluctance Motor (SRM) is returning and today they are being studied by many scientists around the world. This article discusses the torque determination of a Switched Reluctance Motor (SRM) using co-energy. Described is conversion of electrical energy into magnetic field energy and mechanical energy. In these electric machines, the electromagnetic moment is defined as the change in electromagnetic energy due to the change on the angular position of the rotor. The purpose of the study is to find the parameters on which the torque depends in order to form an appropriate control strategy. To simplify the analysis, it is assumed that the machine remains in an unsaturated state during operation – magnetic saturation is neglected, the inductance of the motor depends only on the rotor angle. An exemplary variation of the inductance from the rotor position is shown, which is a direct consequence of the variation of the total magnetic flux and current in the energized phase winding. The areas of operation of SRM are described. Also shown is an exemplary mechanical characteristic of the SRM where the constant torque, constant power, and decelerating power sections are described for low, medium, and high engine speeds. The structure and control principles of the SRM determine the drive characteristics. The basic control strategy involves successive switching of phases at well-defined moments of time. For accurate control it is necessary to account for the highly nonlinear inductance problems and the following ripples of electromagnetic moment. SRM modeling aims to accurately establish the relationship between magnetic flux, torque, current and rotor position, which will contribute to accurate analysis and precise control of these motors. The simulation of SRM 6/4 was made using JMAG-Express software.

Повече

системи и мониторинг
К. В. Велев, Е. И. Велева, Алтернативен подход към удовлетворяване на регионалните енергийни нужди чрез изграждане на общински ютилити клъстери

Статията е 4 от 9 в списание АВТОМАТИКА И ИНФОРМАТИКА 2, 2024 г.

Key Words: Efficiency; energy; social marketing; municipal utility clusters; market with freely negotiated prices.

Abstract. The sale of electricity, heat and natural gas in Bulgaria is characterised by an almost 100% monopoly at regional level. These supplies are licensed on a territorial basis and do not allow local competition. There is a lack of symbiosis between centralised energy and the established regional power plants (mainly PV power stations). This is a serious obstacle to the deployment of RES and the Green Transition that Bulgaria needs. The article discusses the legal framework and proposes an organization at local level for the creation of operating structures – utility clusters for the integration and balancing of energy flows, including those from RES. The regulatory base in Bulgaria allows the creation of such structures in the country. This would solve a number of problems – social, demographic, environmental and purely economic. It is a matter of proper organisation that the energies from these sources are cleverly managed, integrated and balanced as close to the consumer as possible.

Повече

системи и мониторинг
И. Захариев, Определяне на влажността и продължителността на изсушаване на остатъчна биомаса от маслодайна роза при естествено сушене

Статията е 5 от 9 в списание АВТОМАТИКА И ИНФОРМАТИКА 2, 2024 г.

Key Words: Damask rose; drying speed; humidity, energy.

Abstract. The article presents the results of a study of the duration of drying under atmospheric conditions of residual plant biomass generated during the annual contour pruning of the oil rose bushes. The contour pruning of the bushes was done after the completion of the rose bush. The cut biomass is rented from the inter-rows of the arrays. Results of an additional study of this biomass from the same massif stored in bundles in a closed, ventilated warehouse until the end of October are presented. The periods for reaching an air-dry state with a moisture content of 14.38% and below 10% have been determined. Based on the obtained results, a recommendation was made for the use of naturally dried plant biomass. In this way, there is no need for expensive equipment and energy to dry it and bring it into a suitable form for further processing and use.

Повече

новости, информация, общество
Заслужено признание Акад. Минчо Хаджийски със звание „Заслужил деятел на ФНТС“

Статията е 6 от 9 в списание АВТОМАТИКА И ИНФОРМАТИКА 2, 2024 г.

На Общото събрание на Съюза по автоматика и информатика „Джон Атанасов“, проведено на 9 юли 2024 г., доц. д-р инж. Кремена Деделянова, председател на ФНТС, награди със званието „Заслужил деятел на ФНТС“ акад. Минчо Хаджийски – главен редактор на сп. „Автоматика и информатика“.

Повече

новости, информация, общество
Нови професори в областта на автоматиката и информатиката Проф. д-р инж. Христо Вълчанов

Статията е 7 от 9 в списание АВТОМАТИКА И ИНФОРМАТИКА 2, 2024 г.

Христо Георгиев Вълчанов е роден на 4 декември 1963 г. във Варна. Образование и квалификация Проф. д-р Христо Вълчанов е завършил специалност изчислителна техника във ВМЕИ-Варна (сега Технически университет-Варна) през 1989 г. През 1990 г. печели конкурс за асистент към катедра „Изчислителна техника“ към ВМЕИ-Варна. През 2008 г. защитава докторска дисертация на тема „Интегриран подход за обектноориентирана разпределена симулация” (по шифър 02.2 1.04).

Повече

новости, информация, общество
Нови професори в областта на автоматиката и информатиката Проф. д-р инж. Никола Николов

Статията е 8 от 9 в списание АВТОМАТИКА И ИНФОРМАТИКА 2, 2024 г.

Никола Николаев Николов е роден на 26 май 1960 г. в гр. Казанлък. Обучение и квалификации Никола Николов е завършил средно образование в Техникума по електротехника „Мария Кюри“, гр. Сливен, специалност електронна техника.

Повече

in memoriam
90 години от рождението на проф. д.т.н. инж. Никола Маджаров

Статията е 9 от 9 в списание АВТОМАТИКА И ИНФОРМАТИКА 2, 2024 г.

На 5 септември 2024 г. се навършиха 90 години от рождението на уважаемия и обичан проф. д.т.н. инж. Никола Енчев Маджаров (05.09.1934 – 06.06.2022 г.), заместник-декан на ЕФ в МЕИ – София, заместник-ректор на ТУ – София, член на Президиума на ВАК, председател на научна комисия на ВАК, член на научна комисия на ВАК, председател и член на СНС „Автоматика и системи за управление” към ВАК, председател на Научно-консултативния съвет по автоматизация към Съвета за висше образование при МНП, член на редакционните колегии на сп. „Автоматика и изчислителна техника”, „Автоматика, изчислителна техника и автоматизирани системи”, „Автоматика и информатика”, ‟Information Technologies and Control”, член на АС и ФС в ТУ – София, научни, научно-методични и експертни съвети, организационни и програмни комитети в научни мероприятия, притежател е на много награди и отличия.

Повече