Passive Electrical Networks Research Articles

Multimodal vibration damping of a three-dimensional circular ring coupled to analogous piezoelectric networks

Analogous piezoelectric networks have been shown to be effective for multimodal vibration attenuation in structures, including beams, plates, and rings. Previous studies for rings have only accounted for in-plane transverse vibration attenuation and disregarded the out-of-plane vibration modes. Furthermore, these previous numerical models and experiments have only been studied on thin rings, which ignore the effects of shear deformation and rotary inertia. As a result, these networks are not suitable for attenuating vibrations in thick rings. This study enhances on the previous electrical networks, considering both shear deformation and rotary inertia for both in-plane and out-of-plane vibrations. A new passive network topology is developed for the out-of-plane dynamics of thick rings, and the existing passive analogous network of in-plane vibration of thin rings is enhanced by considering the effects of shear deformation and rotary inertia. Combined, these new networks are capable of multimodal vibration damping of a thick ring in three-dimensions, encompassing primarily six types of vibration modes: the inextensional bending modes, the extensional modes, the thickness-shear modes, the coupled twist-bending modes, the torsional modes, and the transverse thickness-shear modes. By using piezoelectric elements to couple two separate analogous passive electrical networks derived from both the in-plane and out-of-plane governing equations of a ring and optimizing the internal resistance in each unit cell, it becomes possible to replicate the dynamics and effectively attenuate different types of vibration modes. This study serves as a theoretical foundation for implementations of passive vibration attenuation in ring structures.

Analogous piezoelectric network for multimodal vibration attenuation of a thin circular ring

Structural vibrations can be reduced by coupling to a piezoelectric electrical network that exhibits analogous modal properties of the structure. This paper considers the multimodal vibration damping of a thin circular ring using this method. The electrical network is derived by applying a finite difference model to the governing equations of motion for a segment of a thin curved beam. An electromechanical analogy is then applied to the physical constants. The resulting passive electrical network unit cell is a topology of capacitors, inductors, and transformers analogous to the dynamics of a segment of curved beam. The electrical network for a curved beam is simplified by considering an inextensional assumption and combining edge components in adjacent unit cells. The resulting simplified discrete network for a curved beam segment is assembled into a complete network for a circular ring. The electrical network for a circular ring displays modal properties similar to its mechanical analogue in both the spatial and frequency domains. As a result of the analogous modal properties across the frequency spectrum, it is shown that the network can be used to achieve multimodal vibration attenuation across a large frequency spectrum. Piezoelectric patches are used to couple the two domains. Numerical simulation of the coupled system demonstrates the effectiveness of the broadband damping effects from the analogous network. Notably, this research establishes a novelty in the field, as it not only introduces experimental validation of curved beam analogues, but also extends the investigation to encompass the coupling between a circular ring and its piezoelectric electrical network counterpart. Further experimental network optimization demonstrate the possibility of tuning the network to adapt to an imperfect mechanical ring.

Decentralized Emergency Control of AC Power Grid Modes with Distributed Generation

Large-scale development of small-scale generation, and facilities based on this, with their integration into existing distribution networks, qualitatively change the modes and tasks of network management and transform previously passive electric networks into active ones. Features of parameters and modes of small-scale generation, insufficient observability and manageability in centralized management determine the need to use a decentralized multi-agent control of the modes of such networks. First of all, this applies to emergency management, which includes automatic restoration of the integrity and normal operation of the network. This paper presents a set of specialized methods for emergency management of active power grid modes and the results of a study of their effectiveness on mathematical and physical models that confirm the feasibility of using decentralized emergency management and network recovery management. In particular, this includes: a method of emergency proactively balanced separation of grid energy districts along one of the a priori fixed network cross-sections in the event of disturbances with the transition to island mode, and a method for two-stage restoration of the integrity and normal network mode with decentralized synchronization of active parts on remote network switches. In the case of the decentralized remote synchronization of active parts, it is proposed to use special control of the excitation and speed of generators to create conditions for the successful operation of automatic reclosing devices with synchronization detection. It is essential for emergency management in active networks with small generation to reject the concept of ensuring the reliability of power supply through maintaining the integrity of the network in favor of the concept of an emergency-balanced breakdown of the network into balanced areas with the subsequent automatic restoration of integrity. To conduct research on the physical model, a prototype of distributed system emergency automation has been developed that does not use data transmission tools, which ensures its high cybersecurity and the feasibility of decentralized management.

Distributed energy resource management systems—DERMS: State of the art and how to move forward

AbstractDue to an ever‐increasing rise in proliferation of distributed energy resources (DERs), the paradigm of passive electrical distribution networks is shifting toward active distribution systems. This new environment introduces a plethora of challenges that cannot be managed by traditional tools, whose utilization could compromise the reliability and efficient operation of distribution feeders. This article systematically reviews state of the art in different DERs management software solutions available today. Additionally, it establishes distinguished roles and responsibilities of different levels of hierarchy in distinct solutions that are all commonly called DERs management systems—DERMS (e.g., fully centralized versus fully decentralized DER management solutions). Lastly, it offers a viewpoint on the directions that hold potential for the power system community and industry to explore for further developments of more robust and intelligent DERMS, to successfully enable efficient transition into a new era of clean and sustainable power systems, encompassing active and dynamically changing distribution circuits.This article is categorized under:Climate and Environment > Net Zero Planning and DecarbonizationEnergy and Power Systems > Distributed GenerationEnergy and Power Systems > Energy Management

Modal-based synthesis of passive electrical networks for multimodal piezoelectric damping

This work presents a new approach to design an electrical network which, when coupled to a structure through an array of piezoelectric transducers, provides multimodal vibration mitigation. The characteristics of the network are specified in terms of modal properties. On the one hand, the electrical resonance frequencies are chosen to be close to those of the targeted set of structural modes. On the other hand, the electrical mode shapes are selected to maximize the electromechanical coupling between the mechanical and electrical modes while guaranteeing the passivity of the network. The effectiveness of this modal-based synthesis is demonstrated using a free–free beam and a fully clamped plate.

Dynamic Identification of Equivalent Parameters of Mathematical Models of Power Electrical Equipment of Electromechanical Power Systems

The article describes a method for dynamic identification of AC and DC hybrid power network parameters. The inaccuracy of the parameters of the electromechanical transient simulation model of the power system has caused the obvious difference between the simulation results and the actual measurement, which has restricted its online application. Over the years, the dynamic parameter identification technology based on field test and test has made great progress, but it is far from satisfactory and accurate. There is still a long research journey for the requirements of performance. The online identification method based on the actual dynamic parameters of the power system is a way to solve the problem. The article includes the main microprocessor modules for system parametric identification of load (SIP L) and an overhead power transmission line (SIP TL). The article will analyze the active electrical network and passive electrical network

CRADLE: Combined RF/Acoustic Detection and Localization of Passive Tags

We introduce CRADLE, or combined RF/acoustic detection and localization, for the remote parametric ranging of passive tags. In this approach, a tag consists of an RF antenna connected to an ultrasonic transducer via a passive electrical network. A reader looks for tags by transmitting both continuous-wave RF and pulsed ultrasound into a region of interest; when a tag is within that region, the ultrasound incident on the tag transducer varies the transducer capacitance, creating a time-varying load for the tag antenna and thus parametrically modulating the RF waves reradiated from the tag. The reader localizes the tag by demodulating the received signal to recover the acoustic time of flight. In this paper, we present a proof-of-concept CRADLE system, describing the design of a custom tag and reader. The results of our localization experiments show that we can achieve sub-decimeter accuracy at reader-tag distances of up to 6 m using the proposed system; future improvements in the design of the tag and reader can result in localization of centimeter-sized tags with sub-centimeter accuracy out to distances of several meters.

Broadband vibration damping of non-periodic plates by piezoelectric coupling to their electrical analogues

Several solutions for multimodal vibration damping of thin mechanical structures based on piezoelectric coupling have been developed over the years. Among them, piezoelectric network damping consists in using piezoelectric transducers to couple a structure to an electrical network, where the transferred electrical energy can be dissipated. In particular, the effectiveness of coupling rods, beams and plates to their analogous electrical networks has been proven. This work is the first step going towards more complex structures. After defining and experimentally validating a fully passive electrical analogous network of a simply-supported plate, the study is extended to the damping of a non-periodic plate. The non-periodicities here studied include the addition of a local mass and a variable thickness. Numerical simulations and experiments show that in these cases, a broadband damping is achieved once the piezoelectric transducers are coupled to an adequate analogous network. A finite element model of the structure coupled to a 2D non-periodic electrical network is concurrently developed and validated, which is another contribution of the present work.

Passively realisable impedance functions by using two fractional elements and some resistors

Here, the necessary and sufficient conditions for realisability of a general class of impedance functions by passive electrical networks composed of two fractional element (fractional capacitor or fractional inductor) and some resistors are found. Also, a systematic procedure is proposed to obtain such passive electrical networks in the realisable cases. Moreover, by establishing a connection with the previously reported researches on the subject of inerter-based passive mechanical control, further results on the maximum number of the resistors required for passive realisation are obtained. Furthermore, a numerical example is presented to show the usefulness of the paper achievements in passive realisation of impedance functions.

Design of a passive electrical analogue for piezoelectric damping of a plate

Vibrations of a mechanical structure can be reduced through a piezoelectric coupling to a passive electrical network exhibiting similar modal properties. For the control of a plate, the design of a two-dimensional analogous electrical network is considered. Depending on the mechanical boundary conditions, a finite difference formulation of the Kirchhoff–Love equation of motion shows that we need to ensure specific electrical connections along the edges of the analogous network. A numerical model involving an assembly of element matrices validates the electrical topology. Then, the passive electrical circuit is implemented with capacitors, inductors, and transformers, whose practical design is closely described. Focusing on the analogue of a clamped plate, experiments prove the ability of the proposed electrical network to approximate the behavior of the mechanical structure.

System Properties of Implicit Passive Electrical Networks Descriptions

Redesigning systems by changing elements, topology, organization, augmenting the system by the addition of subsystems, or removing parts, is a major challenge for systems and control theory. A special case is the redesign of passive electric networks which aims to change the natural dynamics of the network (natural frequencies) by the above operations leading to a modification of the network. This requires changing the system to achieve the desirable natural frequencies and involves the selection of alternative values for dynamic elements and non-dynamic elements within a fixed interconnection topology and/or alteration of the interconnection topology and possible evolution of the network (increase of elements, branches). The use of state-space or transfer function models does not provide a suitable framework for the study of this problem, since every time such changes are introduced, a new state space or transfer function model has to be recalculated. The use of impedance and admittance modeling, provides a suitable framework for the study of network properties under the process of re-engineering transformations. This paper deals with the fundamental system properties of the impedance-admittance network description which provide the appropriate framework for network re-engineering. We identify the natural topologies expressing the structured transformations linked to the impedance-graph, admittance graph-topology of the network and examine issues such as network regularity, number of finite frequencies and provide characterization of them in terms of the basic network matrices. The implicit network representation introduced provides a natural framework for expressing the different types of re-engineering transformations which can be used for the study of the natural frequencies assignment.

Transient Analysis of Switching the Distributed Generation Units in Distribution Networks

<p>Adding distributed Generators (DGs) to the passive electrical networks causes major changes in the specifications of the network including voltage profile, short circuit level and transient stability. In this paper, the effect of DGs switching transient in network is considered. The DGs location are changed in different buses. Two types of DGs are used (i.e. wind and synchronous DGs). Switching transient signals are time variant. It has a continuous spectrum of frequency. Fast Fourier and Wavelet transform methods are used for transient analysis. The proposed method is applied to IEEE-13 Bus distribution system.</p>

Synchronization of harmonic oscillators under restorative coupling with applications in electrical networks

The role of restorative coupling on synchronization of coupled identical harmonic oscillators is studied. Necessary and sufficient conditions, under which the individual systems’ solutions converge to a common trajectory, are presented. Through simple physical examples, the meaning and limitations of the theorems are expounded. Also, to demonstrate their versatility, the results are extended to cover LTI passive electrical networks. One of the extensions generalizes the well-known link between the asymptotic stability of the synchronization subspace and the second smallest eigenvalue of the Laplacian matrix.

Reciprocity of linear systems with smart materials utilized for precise measurement techniques

In electromechanical measurement techniques, passive transducers and passive electrical networks often interact. In some applications, continua are considered as part of the system, where fields are formed and waves are propagated. In this article, networks, continua, and electromechanical transducers feature sufficient amplitude linear behavior in their environment (e.g. for operation around a bias) and are reciprocal. In addition, all elements of the system have constant parameters during the measurement. Then, the skillful application of the inherent reciprocity of these systems can lead to surprisingly useful benefits. This is shown by actual examples from metrology. The examples include the precise determination of transduction coefficients. It is also shown how the linearity of a system is checked by utilizing reciprocity relations. Although the facts of the matter are well known, its potential is often overlooked or disregarded in measurement techniques.

Zero dynamics and funnel control of general linear differential-algebraic systems

We study linear differential-algebraic multi-input multi-output systems which are not necessarily regular and investigate the zero dynamics and tracking control. We introduce and characterize the concept of autonomous zero dynamics as an important system theoretic tool for the analysis of differential-algebraic systems. We use the autonomous zero dynamics and ( E, A, B )-invariant subspaces to derive the so called zero dynamics form – which decouples the zero dynamics of the system – and exploit it for the characterization of system invertibility and asymptotic stability of the zero dynamics. A refinement of the zero dynamics form is then used to show that the funnel controller (that is a static nonlinear output error feedback) achieves – for a special class of right-invertible systems with asymptotically stable zero dynamics – tracking of a reference signal by the output signal within a pre-specified performance funnel. It is shown that the results can be applied to a class of passive electrical networks.

Behavioral Realizations using Companion Matrices and the Smith Form

Classical procedures for the realization of transfer functions are unable to represent uncontrollable behaviors. In this paper, we use companion matrices and the Smith form to derive explicit observable realizations for a general (not necessarily controllable) linear time-invariant behavior. We then exploit the properties of companion matrices to efficiently compute trajectories, and the solutions to Lyapunov equations, for the realizations obtained. The results are motivated by the important role played by uncontrollable behaviors in the context of physical systems such as passive electrical and mechanical networks.

Realizability of Fractional-Order Impedances by Passive Electrical Networks Composed of a Fractional Capacitor and RLC Components

This paper deals with realization of fractional-order impedance functions by passive electrical networks composed of a fractional capacitor and some RLC components. The necessary and sufficient conditions for the existence of such a realization are found in a general case. Also for impedance functions described by a class of fractional-order transfer functions, the realizability conditions are stated as some algebraic conditions on the parameters of the transfer function. Moreover, a procedure is proposed for implementation of such impedance functions by passive electrical networks composed of a fractional capacitor and some RLC components. Numerical examples are presented to show the usefulness of the results of the paper in design of fractional-order electrical circuits.

Multimodal vibration damping of a beam with a periodic array of piezoelectric patches connected to a passive electrical network

A multimodal damping strategy is implemented by coupling a beam to its analogue electrical network. This network comes from the direct electromechanical analogy applied to a transverse lattice of point masses that represents the discrete model of a beam. The mechanical and electrical structures are connected together through an array of piezoelectric patches. A discrete and a semi-continuous model are proposed to describe the piezoelectric coupling. Both are based on the transfer matrix formulation and consider a finite number of patches. It is shown that a simple coupling condition gives a network that approximates the modal properties of the beam. A multimodal tuned mass effect is then obtained and a wide-band damping is introduced by choosing a suitable positioning for resistors in the network. The strategy and the models are experimentally validated by coupling a free-free beam to a completely passive network. A multimodal vibration reduction is observed, which proves the efficiency of the control solution and its potential in term of practical implementation.

Nonlinear Technique for Energy Exchange Optimization in Piezoelectric Actuators

Applications of piezoelectric actuators have increased dramatically during the past few decades. However, the capacitive nature of such devices makes their use delicate, especially in terms of power supply, as the instantaneous power may be much greater than the average effective power. This paper places particular focus on the description of a nonlinear technique for piezoelectric actuator control. This technique enables us to significantly increase the energy transfer efficiency of the device by reducing the reactive part of the power. Such an approach has the inverse effect of the well-known synchronized switch damping technique developed to reduce vibrations in smart structures. The proposed solution consists in disconnecting the driving voltage source from the piezoelectric element and switching the system to a passive electrical network at each occurrence of a voltage extremum. This switching strategy is designed to annihilate the reactive energy supplied by the voltage source and to decrease the active energy while ensuring a constant output power. Suppressing the reactive energy is particularly interesting for limiting the dimensions and energy requirements of power supplies. Compared to classical methods, the direct supply of both simulations and experimental validations has demonstrated the effectiveness of the proposed technique for eliminating all of the reactive energy and reducing the active power at frequencies close to the resonant one, while maintaining similar mechanical performances.

Effects of dynamic and non‐dynamic element changes in RC and RL networks

AbstractThe paper deals with the redesign of passive electric networks by changes of single dynamic and non‐dynamic elements which may retain or affect the natural topology of the network. It also deals with the effect of such changes on the natural dynamics of the network, the natural frequencies. The impedance and admittance modeling for passive electrical networks is used which provides a structured, symmetric, integral‐differential description, which in the special cases of RC and RL networks is reduced to matrix pencil descriptions. The transformations on the network are expressed as those preserving, or modifying the two natural topologies of the network, the impedance graph and the admittance graph topologies. For the special cases of RC and RL networks, we consider the problem of the effect of changes of a single dynamic or non‐dynamic element on the natural frequencies. Using the Determinantal Assignment Framework, it is shown that the family of single parameter variation problems is reduced to equivalent Root Locus problems with the possibility of fixed modes. An explicit characterization of the fixed modes is given, and a number of interesting properties of the spectrum are derived such as the interlacing property of poles and zeros for the entire family of Root Locus problems. Copyright © 2013 John Wiley & Sons, Ltd.