Electrical Port Research Articles

Field-circuit coupling model of triboelectric nanogenerators

High-entropy energy conversion and storage based on triboelectric nanogenerators (TENGs) has attracted substantial interest in recent years. Not only a large number of theoretical models but also experimental works have been focusing on confirming optimum conditions and prediction of maximum outputs of TENGs, which is in order to enlarge power generation and energy conversion efficiency. A complete power analysis of TENG systems includes the mechanical input (mechanical port), a TENG transducer, and electrical output (electrical port). However, the relationships between the external force driving TENG and the generated instantaneous power as well as the energy flowing inside TENGs remain elusive. Here, a dynamic field-circuit coupling model composed of a quasi-electrostatic field and an external circuit is established that allows the determination of the force distribution and power flow of a TENG transducer. It is confirmed that dissipation in TENGs is entirely electrical and caused by the separation of charges distributed in contacting surfaces and metal electrodes. Importantly, in steady-state operation, all input energy is converted into electrical (useful) power unless dissipation mechanisms (mechanical and electrical). In addition, the essential factors which affect the basic output characteristics of TENGs are discussed. This work suggests a new approach to fully understanding the whole dynamic power-delivering process within TENGs which is essential for the theoretical optimization of TENG performance and practical applications of TENGs.

Predictive Modeling of MEMS via Generic Meminductors: The Multiport Inductor Approach

It is shown for the first time that a large class of generic meminductors with a specific form of the state equation can be constructed from elements of Chua’s periodical table and a multiport inductor. The electrical port of this inductor is identical to the physical port of the meminductor. The other ports, which may be of general, i.e. not electrical nature, interconnect the processes that make up the overall dynamics of the element. This result allows creating predictive models of a wide range of existing MEMS (Micro-Electro-Mechanical Systems) exhibiting the behavior of generic meminductors. A model building procedure is described using the example of an elastic meminductive system. The model is then implemented in SPICE and verified by computer simulations.

Mapping of Dynamics Between Mechanical and Electrical Ports in SG-IBR Composite Grids

Power grids are traditionally dominated by synchronous generators (SGs) but are currently undergoing a major transformation due to the increasing integration of inverter-based resources (IBRs). The state space method with transparent apparatus models can be readily used. However, models of IBRs are usually not disclosed by manufacturers. Alternatively, the port-based approach represents dynamics by input-output transfer functions without exposing internal states. These transfer functions at various ports are normally configured with a particular focus: an SG-dominated grid is traditionally analyzed in a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mechanical-centric</i> view which ignores fast electrical dynamics and focuses on the torque-speed dynamics, whereas the emergent IBR-dominated grid usually takes an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">electrical-centric</i> view which focuses on the voltage-current interaction. In this article, a new perspective called the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">port-mapping method</i> is proposed to combine these two views. Specifically, the mechanical dynamics are mapped to the electrical impedance seen at the electrical port; and the electrical dynamics are also mapped to the torque coefficient seen at the mechanical port. The bidirectional mapping gives additional flexibility and insights to analyze the sub-system interactions in whole-system dynamics and guide the tuning of parameters. Application of the proposed method is illustrated in three cases with increasing scales.

RL-Ladder Circuit Models for Eddy-Current Problems With Translational Movement

This article proposes an adaptive equivalent <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$RL$ </tex-math></inline-formula> -circuit model for eddy-current devices with a single electrical port (one terminal voltage and current) and translational movement. The device is first characterized by means of frequency-domain finite-element computations in the relevant frequency and position intervals, for subsequently fitting constant-coefficient <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$RL$ </tex-math></inline-formula> -ladder circuits of adjustable size (i.e., variable number of branches and loops). The accuracy of the ladder-circuit model is assessed in both the frequency and time domains. The time-varying position involves the force computation from the circuit and the coupling with the mechanical equation. By way of validation, we study the axisymmetric magnetic-levitation device of TEAM Workshop problem 28. Results exhibit good convergence to reference finite-element ones with increasing number of branches.

Design and implementation of a parametric battery emulator based on a power converter

Real batteries used for the performance testing and evaluation of the drive systems of electric vehicles (EVs) are being replaced by battery emulators (BEs) because of the high test costs, long test cycles, and difficulty in adapting to extreme operating conditions associated with the use of real batteries. A parametric BE for a lithium-ion battery based on a voltage source converter is presented. First, a Thevenin model of the battery is established, and a parameter identification method is proposed to obtain the relationship between the parameters of the battery model and the characteristics of the external electrical port (i.e. I–V characteristics) of the battery. Subsequently, based on the I–V characteristics, the topological structure of the power electronic device of the BE is designed, and the working modes under charging and discharging conditions are presented. Finally, an experimental prototype of the BE is designed and tested. The experimental results show that the proposed BE power converter can successfully simulate the external port voltage and current characteristics of the battery, which can replace the real battery to provide an effective test environment for the test and evaluation of the electric drive system of EVs.

Accurate Calibration and Measurement of Optoelectronic Devices

Frequency responses of optoelectronic devices are essential to obtain the precise performance of electrical-to-optical-to-electrical signal conversion or optical signal processing. We reviewed the development of optical or electrical measurement methods proposed for characterizing electrical/optical (E/O) devices, optical/electrical (O/E) devices and optical/optical (O/O) devices in the frequency domain from the perspective of accurate calibration standard. It has been found that full calibrated E/O or O/E measurement requires at least an optoelectronic thru standard for the conversion between optical and electrical domains, and an electrical port extension for de-embedding the error or adapter network of microwave source or detector. The indetermination problem still exists in most O/E and E/O device characterization, which appears in different forms for different measurement techniques. Nevertheless, it should be noticed that obtaining an optoelectronic thru standard can be transferred to characterizing a microwave source or detector in the electrical domain, and a precise electrical calibration standard is much easier to be obtained as compared with an optoelectronic calibration standard. Therefore, the calibration standard transfer from optical to electrical domain is a prominent approach to solve the indetermination problem.

Wireless power transfer: a review

- The ubiquitous nature and the proliferation of mobile devices has made wireless power transfer (WPT) a very important area of research. The flexibility and cost effectiveness of charging these enormous devices in our world without having to connect physically to any electrical port especially when the user is indisposed to do so is a very attractive characteristic of WPT. Conventional means of charging the batteries of these mobile devices are wired which invariably meansthey requirephysical connection to power sources through electrical cables. Electric power istransmitted wirelessly when a magnetic field produced by the inductive coupling of coils or electrical field produced by the capacitive coupling between electrodes is transferred over a short distance through the air interface and later received by an antenna for utilisation. This article gives a detailed review of the existing wireless power transfer technologies, principles of operation, applications and the opportunities for future research in this area of emerging technology. However, WPT has some drawbacks but it is a disruptive technology with the ability to revolutionise the dynamics of mobile wireless systems, internet of things and otherallied future technologies.

Investigation of Regenerative Braking Performance of Brushless Direct Current Machine Drive System

The brushless direct current (BLDC) machines which are preferred in light electric vehicles (LEVs) come forward as high regenerative braking capability machines due to their permanent magnet excitation and relatively simple operation. In this paper, the regenerative braking capability limits of BLDC machines and their drive circuits are examined by taking into account nonlinear circuit parameters and battery internal resistance variation. During energy recovery from mechanical port to electrical port, the inverter of BLDC machine is operated as a boost converter which enables power flow to a battery. However, the regeneration performance is also heavily dependant on the battery condition, particularly the temperature. By means of the developed detailed circuit model including the non-ideal effects of the boosting converter and the increase of the internal resistance variation which is caused by the temperature variation of the battery and ambient temperature, the specific duty cycle can be determined. The specific duty ratio is then applied in a proposed approach for various operation scenarios. The experimental tests are implemented by a 400 W BLDC machine drive system controlled via a TMS320F28335 digital signal processor. The experimental results show that the proposed comprehensive model presents a proper performance estimation of regenerative braking system under varying battery temperature.

Image rejection mixer based on a bidirectional phase modulator with full-spectrum utilization

ABSTRACTAn all-optical image rejection (IR) mixer, based on a dual electrical port phase modulation (PM) in a Sagnac loop and a wavelength division multiplexer (WDM), is proposed. The radio frequency (RF) and the local oscillator signals are loaded onto the two electrical ports of the PM, respectively. The two down-conversion channels are obtained with the use of WDM. A pair of phase orthogonal down-converted intermediate frequency (IF) signals are obtained by properly adjusting polarization controller. Then an electrical low-frequency 90 hybrid coupler (90HC) combines the two IF signals to double the desired IF signal and suppress the image interference IF signal. In the simulation, a 30-GHz RF signal is successfully down-converted to 1 GHz with about 57 dB IR. Compared with the IR mixer based on two parallel PMs, conversion efficiency is improved about 6 dB.

A microfluidics-integrated impedance/surface acoustic resonance tandem sensor

We demonstrate a dual sensor concept for lab-on-a-chip in-liquid sensing through integration of surface acoustic wave resonance (SAR) sensing with electrochemical impedance spectroscopy (EIS) in a single device. In this concept, the EIS is integrated within the building blocks of the SAR sensor, but features a separate electrical port. The two-port sensor was designed, fabricated, and embedded in a soft polymer microfluidic delivery system, and subsequently characterized. The SAR-EIS tandem sensor features low cross-talk between SAR and EIS ports, thus promoting non-interfering gravimetric and impedimetric measurements. The EIS was characterized by means of the modified Randle's cell lumped element model. Four sensitive parameters could be established from the tandem sensor readout, and subsequently employed in a proof of principle study of liposome layers and their interaction with Ca2+ ions, leading to transformation into molecular film structures. The associated shift of the sensing quantities is analysed and discussed. The combination of impedimetric and gravimetric sensing quantities provides a unique and detailed description of physicochemical surface phenomena as compared to a single mode sensing routine.

A high-performance lab-on-a-chip liquid sensor employing surface acoustic wave resonance: part II

We recently introduced an in-liquid sensing concept based on surface acoustic resonance (SAR) in a lab-on-a-chip resonant device with one electrical port. The 185 MHz one-port SAR sensor has a sensitivity comparable to other surface acoustic wave (SAW) in-liquid sensors, while offering a high quality factor (Q) in water, low impedance, and fairly low susceptibility to viscous damping. In this work, we present significant design and performance enhancements of the original sensor presented in part I. A novel ‘lateral energy confinement’ (LEC) design is introduced, where the spatially varying reflectivity of the SAW reflectors enables strong SAW localization inside the sensing domain at resonance. An improvement in mass-sensitivity greater than 100% at resonance is achieved, while the measurement noise stays below 0.5 ppm. Sensing performance was evaluated through real-time measurements of the binding of 40 nm neutravidin-coated SiO2 nanoparticles to a biotin-labeled lipid bilayer. Two complementary sensing parameters are studied, the shift of resonance frequency and the shift of conductance magnitude at resonance.

A Novel Axial Flux Magnetically Geared Machine for Power Split Application

This paper proposes an axial flux magnetically geared (AFMG) permanent magnet (PM) machine for power split application in hybrid electric vehicles. The proposed AFMG machine has the merits of simple structure and improved torque density by combining a magnetic gear with a PM machine. The machine can realize power split with the help of dual mechanical ports and one electrical port, i.e., the input mechanical power and/or electrical power produced by the machine can be split or integrated. The operation principle and two feasible stator slot/rotor pole combinations are analyzed. Moreover, the influence of the machine parameters on the output torque as well as the performance of both combinations are investigated and compared by using JMAG three-dimensional finite element analysis (FEA). In addition, the method of boosting the machine torque is described and experiment results of the proposed machine prototype are provided and compared with FEA results.

Three-port equivalent circuit of multi-layer piezoelectric stack

Multi-layer piezoelectric transducers (MPS) is a transducer stacked by numerous thin piezo layers, which can used as an actuator, sensor, or energy harvester. This paper points out the limitations of existing equivalent circuits for the effective modelling of MPS and proposes a 3-port equivalent circuit of MPS which is inspired by the idea of network theory and formulated exactly on the basis of the simplified fundamentals. The 3-port equivalent circuit, which separates the MPS into two acoustic ports and one electrical port through an electro-mechanical transformer, offers an exact and explicit representation of electro-mechanical coupled interaction of MPS. It is very straightforward to apply and effectively simplifies and facilitates the analysis, modelling, and calculation of free and loaded vibration of MPS in either transmitter mode (actuator) or receiver mode (sensor or energy harvester). Compared with existing circuit models in literature, the proposed circuit can be extended to any electrical and mechanical condition. Besides, as the proposed circuit elements are explicitly and exactly derived in terms of material and dimension information rather than determined from measured information, the proposed circuit model allows one to predict behaviors with material properties and structural dimension. For validation, a simple case study is carried out. For both free and loaded vibrations of MPS in the case study, the effectiveness of the proposed circuit has been validated by 3D FEA models.

In-House Development of Shear Horizontal Acoustic Waves Based Sensitive Sensors for Bacterial Pathogens Detection

Surface acoustic wave can be generated at the free surface of an elastic solid. Interdigital transducers (IDTs) are fabricated on the piezoelectric substrate surface that will act as electrical input and output port. When appropriate AC voltage stimulus is applied to the input transducer, surface acoustic wave will be produced. The output or receiving port will detect the incident surface acoustic wave and convert it back to a suitably filtered electrical once. For this property, surface acoustic based devices were initially developed for the telecommunication purpose such as signal filters and resonators. SAW based devices have been modified to be sensors later on from for gas detections and have been moving towards biological detections recently for its ultra-sensitivity to surface perturbation. The main component of this device is the IDTs. Recently, there are several methods to produce IDTs; Ultra-Violet (UV), deep UV lithography, Electron beam (e-beam) lithography and X-ray lithography. Although, these methods can produce very fine and accurate electrodes in term of submicron size but the costs are extremely expensive. Thus, this paper will discuss the conventional CMOS method which is much more economical to produce the applicable IDTs for the bacterial pathogens sensing purpose. Shear horizontal surface acoustic wave (SHSAW), one of the SAW based types is used in this paper as it is most suitable for the liquid based application as it has the advantage of acoustic energy is not being radiated into liquid.

Development of high sensitivity, large frequency bandwidth ZnO-based accelerometers

ZnO has excellent capability in micromachining process for the fabrication of miniaturized accelerometer but its sensitivity is lower because the piezoelectric effect of ZnO is poor. In this paper, a novel accelerometer was made by ZnO and the real part of electrical impedance of ZnO accelerometer at its electrical port was employed to improve its sensitivity. The proposed method is able to obtain active, time varying real part of electrical impedance which correlates with the measured acceleration, usually experienced at the mechanical port of ZnO accelerometer. By comparing with the conventional approach which relies on the output voltage of ZnO accelerometer, the sensitivity is improved almost double with relatively low linearity error and large full scale output. Furthermore, the frequency bandwidth of ZnO accelerometer is extended up to its resonance frequency because the measurement of acceleration is done at the resonance frequency of ZnO accelerometer. Therefore, it allows the ZnO accelerometer to operate at its full frequency bandwidth since the unity response of ZnO accelerometer is no longer limited by the frequency response function of ZnO accelerometer.

Generalised relations between P ‐ and Y ‐matrices and their applications

The P -matrix is commonly used to analyse surface acoustic waves (SAW) elements such as the interdigital transducer (IDT) but, when some IDTs are connected through their acoustic ports, their frequency response could be calculated easily in terms of their admittances. Instead of the P -matrix, Y -matrix also allows coupling of the system to another electric or electronic device. Here, the authors present a general method to obtain the Y -matrix (with size N × N) of a SAW device with N electrical terminals connected to N different voltage sources. This method considers the reflections from the edges or any other non-electrical elements that can cause reflections beyond P -matrices. In addition, it has been shown that when there are no reflections and there are two P -matrices, this method converges to well-known previous results. Furthermore, the authors present two cases that could be used to analyse a SAW device: the input admittance and the equivalent P -matrix for a SAW device when a Y -matrix is connected to the electrical port of the SAW device. Also, the authors have calculated the acoustic relations for two SAW devices connected through their electric ports. Furthermore, these methods are exemplified through their application to a SAW system composed of three different IDTs and to an IDT and an inductor connected to its electrical port.

Bidirectional Millimeter-Wave Radio-Over-Fiber System Based on Photodiode Mixing and Optical Heterodyning

We demonstrate a bidirectional millimeter-wave (mmW) radio-over-fiber system based on the use of a p-i-n photodiode (PD) biased in the nonlinear regime. Since frequency down-conversion and photodetection are carried out by a single photodiode, the base station (BS) architecture is simplified. Down-link transmission employs an optical heterodyning technique for mmW generation and remote local oscillator (LO) delivery to BSs. The up-link scheme uses the electrical port of the PD as an input for optoelectronic mixing with the remotely delivered LO. Up-link and down-link have been successfully demonstrated for 397 Mbps and 794 Mbps binary phase-shift keying complying with the 60 GHz ECMA 387 standard. Error vector magnitude measurements and theoretical analysis are discussed as regards optimal PD bias conditions. It is shown that PD can be used in this bidirectional system without any switching of the PD bias.

Photonic Heterodyne Pixel for Imaging Arrays at Microwave and MM-Wave Frequencies

The use of photonic heterodyne receivers based on semiconductor optical amplifiers to be used in imaging arrays at several GHz frequencies is evaluated. With this objective, a imaging array based on such photonic pixels has been fabricated and characterized. Each of the receiving optoelectronic pixels is composed of an antipodal linear tapered slot antenna (LTSA) that sends the received RF signal directly to the electrical port of a semiconductor opticalamplifier (SOA) acting as the optoelectronic mixer. Both the local oscillator (LO) and the intermediate frequency (IF) signals are directly distributed to/from the array pixels using fiber optics, that allows for remote LO generation and IF processing to recover the image. The results shown in this work demonstrate that the performances of the optoelectronic imaging array are similar to a reference all-electronic array, revealing the possibility of using this photonic architecture in future high-density, scalable, compact imaging arrays in microwave and millimeter wave ranges.

Impact of electrical grooming and regeneration of wavelength paths in creating hierarchical optical path networks

We assess the impact of utilizing electrical cross-connects for the intermediate grooming and 3R regeneration of wavelength paths in a hybrid hierarchical optical path network. Simulation results prove that they offer a significant cost reduction. We also investigate the dependencies of network cost on network parameters including optically-transparent reach, electrical switch port cost, and waveband capacity. It is demonstrated that it is critical to choose the waveband capacity properly in order to minimize total network cost.

2-D modeling of laterally acoustically coupled thin film bulk acoustic wave resonator filters

A 2-D model is developed for calculating lateral acoustical coupling between adjacent thin film BAW resonators forming an electrical N-port. The model is based on solution and superposition of lateral eigenmodes and eigenfrequencies in a structure consisting of adjacent regions with known plate wave dispersion properties. Mechanical and electrical response of the device are calculated as a superposition of eigenmodes according to voltage drive at one electrical port at a time while extracting current induced in the other ports, leading to a full Y-parameter description of the device. Exemplary cases are simulated to show the usefulness of the model in the study of the basic design rules of laterally coupled thin film BAW resonator filters. Model predictions are compared to an experimental 1.9-GHz band-pass filter based on aluminum nitride thin film technology and lateral acoustical coupling. Good agreement is obtained in prediction of passband behavior. The eigenmode-based model forms a useful tool for fast simulation of laterally coupled acoustic devices. It allows one to gain insight into basic device physics in a very intuitive fashion compared with more detailed but heavier finite element method. Shortcomings of this model and possible improvements are discussed.