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1
Content available A power shaping based control strategy for dual active full-bridge converter
Zhang Yajing, Ma Hao, Wang Xiuteng, Shao Tiancong
Archives of Electrical Engineering
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2024
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Vol. 73, nr 2
543--556
EN
Dual active full-bridge (DAB) DC–DC converters are widely used in DC microgrids and various fields of power electronics. It has the advantages of high-power density, easy to implement soft switching and bi-directional power transfer capability. Conventional linear controllers have difficulty in meeting the increasing demands for speed and robustness. In this paper, a control strategy based on the Brayton–Moser theory of power shaping is proposed to improve the control strategy of DAB DC–DC converters. The DAB DC–DC converter is modelled and the controller is designed based on the Brayton–Moser power-shaping theory. A simulation of the DAB DC–DC converter is constructed and a comparative analysis is carried out for three control strategies of PI control, passive control and power-shaping Brayton–Moser control under different operating conditions.
2
Content available remote Development of a new hexagonal honeycomb steel damper
Javanmardi Ahad, Ghaedi Khaled, Ibrahim Zainah, Huang Fuyun, Xu Pu
Archives of Civil and Mechanical Engineering
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2020
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Vol. 20, no. 2
490--508
EN
This paper presents a new metallic damper called hexagonal honeycomb steel damper (HHSD) for damage mitigation in structures subjected to earthquake excitations. The HHSD is composed of steel plates having several hexagonal and welded to the top and bottom anchor plates. The damper takes the advantages of hexagonal honeycomb geometry and steel material capability to dissipate seismic energy. The quasi-static cyclic test was performed experimentally and numerically on a series of specimens to evaluate the robustness of the HHSD. A three-dimensional finite element analysis of HHSD was carried out and verified with the experimental results. The results showed that the HHSD has low yield displacement, stable hysteretic behavior, a good range of ductility and high-energy dissipation capability. Additionally, the constitutive formulas of the damper are also derived based on the obtained results. Furthermore, it is found to have lightweight and inexpensive with ease of implementation as a potential alternative for new structures or seismic retrofitting of the existing structures.
3
Content available Hybrid passivity based and fuzzy type-2 controller for chaotic and hyper-chaotic systems
Serrano F., Rossell J. M.
Acta Mechanica et Automatica
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2017
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Vol. 11, no. 2
96--103
EN
In this paper a hybrid passivity based and fuzzy type-2 controller for chaotic and hyper-chaotic systems is presented. The proposed control strategy is an appropriate choice to be implemented for the stabilization of chaotic and hyper-chaotic systems due to the energy considerations of the passivity based controller and the flexibility and capability of the fuzzy type-2 controller to deal with uncertainties. As it is known, chaotic systems are those kinds of systems in which one of their Lyapunov exponents is real positive, and hyperchaotic systems are those kinds of systems in which more than one Lyapunov exponents are real positive. In this article one chaotic Lorentz attractor and one four dimensions hyper-chaotic system are considered to be stabilized with the proposed control strategy. It is proved that both systems are stabilized by the passivity based and fuzzy type-2 controller, in which a control law is designed according to the energy considerations selecting an appropriate storage function to meet the passivity conditions. The fuzzy type-2 controller part is designed in order to behave as a state feedback controller, exploiting the flexibility and the capability to deal with uncertainties. This work begins with the stability analysis of the chaotic Lorentz attractor and a four dimensions hyper-chaotic system. The rest of the paper deals with the design of the proposed control strategy for both systems in order to design an appropria.
4
Content available remote Passive Control of Shock Wave Applied to Helicopter Rotor High-Speed Impulsive Noise Reduction
Doerffer P., Szulc O.
TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk
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2010
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Vol. 14, No 3
297-305
EN
A strong, normal shock wave, terminating a local supersonic area on an airfoil (or a helicopter blade), not only limits the aerodynamic performance, but also becomes a source of High-Speed Impulsive (HSI) noise. The application of a passive control system (a cavity covered by a perforated plate) on a rotor blade should reduce the noise created by the moving shock. This article describes numerical investigations focused on the application of a passive control device on a helicopter blade in high-speed transonic hover conditions to weaken the shock wave – the main source of HSI noise.
5
Minimalizacja drgań fundamentu z maszyną
Gołębiowska I., Sakiewicz W.
Inżynieria i Aparatura Chemiczna
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2006
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Nr 3 sp.
30-31
EN
Some methods of construction protection against vibrations are described in the paper. Research results dealing with the efficiency of a multilevel multi-tuned mass damper applied to minimize foundation vibrations with the machine on vibration insulation are presented. It was found that the efficiency of analysed tuned mass damper depended significantly on the mass distribution coefficient in respective levels.
6
Content available remote Shock wave smearing by wall perforation
Doerffer P., Szulc O.
Archives of Mechanics
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2006
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Vol. 58, nr 6
543-573
EN
Normal shock wave, terminating a local supersonic area on an airfoil, not only limits aerodynamic performance but also becomes a significant source of a high-speed impulsive noise on the rotor blade of a helicopter. It is proposed to apply passive control to disintegrate the shock wave by smearing pressure gradients created by the shock. Details of the flow structure obtained by this method are studied numerically. A new boundary condition of a perforated wall is verified against experimental data for a passive control of the shock wave in a channel flow and on an airfoil. This method of shock wave disintegration is proven to work for internal flows in transonic nozzles and appears to be effective for transonic airfoils as well. The substitution of a shock wave by a gradual compression changes completely the source of the high-speed impulsive noise and bears potential of its reduction.
7
Content available remote An analysis of a piezo-elastic restrictor using a capacitive shunt
Kekana M., Badur J.
TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk
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2004
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Vol. 8, No 3
377-384
EN
The study investigates the control of structural response using collocated piezoelectric elements mounted on both sides of beam. A capacitive shunt is introduced into the circuitry to provide passive control of the beam's configuration. The energy method is used to develop the structure's governing equations. In order to select the appropriate electrostatic relations for the material, i.e. conductor or insulator material, the free charge rearrangement time is used. The effects of the capacitive shunt are introduced into the electrostatic relations using additive decomposition of capacitance. As an application of the model, a piezo-elastic beam restrictor using a capacitive shunt is investigated. Numerical results show that the capacitive shunt can effect passive control of the configuration of the beam.
8
Content available Some aspects of vibration control. Part I: Active and passive correction
Kosowski K.
Polish Maritime Research
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2004
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nr 4
22-27
EN
The paper presents a general approach to mechanical system modification aimed at controlling the steady harmonic vibrations by means of passive and active methods. The relaŹtive decrease of harmonic vibration amplitudes of selected elements of the mechanical system has been chosen as a measure of the quality of the introduced modification. The proposed theoretical method enables to determine the parameters of the system’s dynamic flexibility matrix, which show the most remarkable effect on the dynamic behaviour of the whole system. When active control is considered the method is useful in designing the structure and choosing the parameters of the control system. In certain in cases of self-excited vibration the approach helps examining the elements of the system, most responsible for this kind of excitation.
9
Content available remote Passive control of a beam subject to travelling
Bajer Cz., Bogacz R., Imiełowski Sz.
Engineering Transactions
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2000
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Vol. 48, iss. 3
283-292
EN
The subject of the study is the minimization of transverse vibration of elastic guideway excited by high-speed travelling inertial load. Two types of systems of passive control are considered, the post truss system and the dynamic vibration absorbers. In the first one, the beam is supported by posts fixed to the beam span and prestressed by tendons connected to the ends of beam. The considered system corresponds to the experimental test stand. It is modelled by a simply supported Bernoulli-Euler beam, where the material passive damping is represented by means of the Voigt model. In the system the control is performed by point transverse forces and bending moments applied to the beam span. The significant reduction of the amplitude of vibrations is achieved for a guideway supported by truss system consisting of two posts. The obtained results are compared with the data obtained for active control of the considered guideway.
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