Impedance Network Research Articles

Modelling and DPWM control of continuous switched boost inverter

ABSTRACT In this paper, a new type of three-phase continuous switched boost inverter (CSBI) is proposed. The proposed inverter has a new impedance network that can obtain a high voltage boost ratio. It also can make the system work in continuous conduction mode (CCM). The shoot-through is allowed in the operating mode of the CSBI, which eliminates the dead time and leads to better EMI immunity. The modified discontinuous pulse-width modulation (DPWM) strategy is proposed to operate the CSBI. Compared with the space vector pulse-width modulation (SVPWM) method, the new modulation strategy can reduce the switching loss effectively. Meanwhile, the state space averaging method is used to design the inverter structure and calculate the impedance parameters. To investigate the dynamic performance of the CSBI impedance parameters, the small signal model analysis is used. A test bench of CSBI is built in laboratory. The operating strategy and the theoretical analysis of the proposed inverter are validated by the results of simulation and experiment.

Low-Contact Impedance Textile Electrode for Real-Time Detection of ECG Signals.

The quality of the electrocardiography (ECG) signals depends on the effectiveness of the electrode-skin connection. However, current electrocardiogram electrodes (ECGE) often face challenges such as high contact impedance and unstable conductive networks, which hinder accurate measurement during movement and long-term wearability. Herein, in this work, a bionic 3D pile textile as an ECGE with high electrical conductivity and flexibility is prepared by a facile, continuous, and high-efficiency electrostatic self-assembly process. Integrating pile textiles with conductive materials creates a full textile electrode for bioelectrical signal detection that can retain both the inherent characteristics of textiles and high conductivity. Moreover, the dense piles on the textile surface make full contact with the skin, mitigating motion artifacts caused by the sliding between the textile and the skin. The continuous conductive network formed by the interconnected piles allows the pile textile ECGE (PT-ECGE) to function effectively under both static and dynamic conditions. Leveraging the unique pile structure, the PT-ECGE achieves superior flexibility, improved conductivity, low contact impedance, and high adaptivity, washability, and durability. The textile electrode, as a promising candidate for wearable devices, offers enormous application possibilities for the unconscious and comfortable detection of physiological signals.

Anomalous power-law behavior in the electrical impedance of endothelial cellular networks

In this paper, we report on the electrical impedance measurement of human endothelial cellular networks and show the existence of emergent power law behavior in its admittance. In particular, we find that the admittance scales with the frequency ω as ωα, with the exponent that varies with the degree of the disruption caused by the inflammation in the endothelial cellular network. We demonstrate that the power law of the measured electrical admittance can be understood by a simple percolation model of a large R–C (resistor–capacitor) network, which allows us to relate quantitatively and the intensity of inflammation. Our results suggest that the electrical properties of heterogeneous biomaterials, like living tissues, behave as a complex microstructural network.

A Compact Broadband Rectifier Based on Coupled Transmission Line for Wireless Power Transfer

Wireless Power Transfer (WPT) can effectively solve the problem of autonomous power supply for low-power devices. Rectifier is the key component in WPT technology. In this paper, a novel impedance matching network for the broadband rectifier is proposed. This impedance matching network compensates for the diode impedance and reduces its impedance change when the frequency or input power changes. The passive boosting mechanism utilizing coupled transmission lines (CTLs) improves the power conversion efficiency (PCE) of the diode in the low power region. The structure is especially optimized for low-power device applications. For validation, a broadband rectifier operating at 1.9–3 GHz is fabricated and measured. The structure fabricated on the Rogers 4003 substrate with a thickness of 1.508 mm and the diode is HSMS2860. The DC voltage Vout on the load (RL=1300 Ω) was measured. The results show that at 0 dBm, the PCE keeps more than 60% at 1.98–3 GHz. The peak PCE of 79.6% is obtained at 4 dBm. The compact size of the broadband rectifier is 19 mm × 21 mm. This broadband rectifier for low input power ranges can be applied to WPT technology.

Quasi‐Z‐source interleaved DC‐DC converter for fuel cell vehicle application

AbstractIn this study, a step‐up DC‐DC converter with a combination of a two‐phase interleaved structure and a quasi‐Z impedance network is proposed for fuel cell vehicle application. The operation of the converter in a small duty cycle (0 < D < 0.5) reduces the conductive losses of the switches and as a result increases the efficiency of this converter compared to conventional boost converters. Also, due to the common ground between the input and output, unlike the floating interleaved boost converter (FIBC) and the parallel input‐series output converter (PISO), it does not face the problem of imposing additional EMI on the converter circuit. This converter has a low input current ripple, suitable voltage gain for fuel cell vehicles system, as well as high reliability due to the ability to operate with one phase in case of failure in the other phase. It can be a suitable candidate for practical application in fuel cell vehicles. The principles of operation and the main characteristics of the converter such as voltage gain, input current ripple, and voltage and current stress of the elements are explained and also a 120‐W experimental prototype with 12‐V input voltage and 60‐V output voltage is made to validate the theoretical analysis results.

A compact dual‐band bandpass filter based on coupled stub‐loaded square ring resonators by using transversal signal‐interaction concepts

AbstractIn this paper, a novel dual‐band wideband bandpass filter (BPF) based on transversal signal‐interaction concepts with a wide upper stopband is proposed and investigated. The designed specification of two passbands can be managed and satisfied based on the independent controllable fractional bandwidth of the two passbands and the centered frequencies. The centered frequencies of dual‐band BPF are, respectively, 0.79 GHz (ƒ1) and 1.24 GHz (ƒ2) with 3 dB fraction bandwidths of 26.54% and 11.3%. Two transmission paths consisting of coupled stub‐loaded square ring resonators and anti‐coupled shorted lines are used to realize signal cancellation of multiple transmission path signal transmission from Port 1 to Port 2. Eleven transmission zeros (TZs) modify harmonic suppression up to 10 ƒ1 with stopband rejection higher than 15 dB. Butterworth lumped notch network and step impedance resonator (SIR) are also utilized to improve the selectivity and harmonic suppression. A compact filter with a circuit size of 0.08λg × 0.08λg is implemented and tested. Good agreement between simulation and measured results verifies the reliability of the designing scheme.

Dual Second Order Generalized Integrator – Phase Locked Loop technique applied to a distorted grid-connected solar energy based on a Z-Source Inverter

In this paper, a Dual Second Order Generalized Integrator_Phase Locked Loop (DSOGI_PLL) technique applied to the Photovoltaic (PV) system supplying a Z-Source five-level Inverter (ZSI) is presented. The ZSI assures the increasing voltage of the PV system and provides the desired output DC at the input of the five-level Neutral Point Clamped Inverter (5L_NPCI), without any control which reduces the complexity of the overall system, this is due to the impedance network in its structure. We use Z-Source in order to eliminate the controlled DC bus as well as the use of the DC-DC Boost converter as an intermediary. A DSOGI technique is employed to control and optimize the energy quality, especially in distorted grid conditions and allows one to obtain a very low value of Total Harmonic Distortion (THD) which means lower peak currents, and higher efficiency. Low THD is an essential feature in power systems that international standards such as IEC 61000-3-2, and IEEE-519 set limits on the harmonic currents of various classes of power equipment connected to a distorted three-phase grid. Compared to the classic structure of inverters, the NPC five-level inverter presents a very high performance.

Design of X-Band GaN LNA MMIC with Switched Impedance Network for Improved Noise Figure

Design of X-Band GaN LNA MMIC with Switched Impedance Network for Improved Noise Figure

A high gain quasi Z‐source based full‐bridge isolated DC‐DC converter with extendable structure for grid‐tied/standalone PV system

AbstractA multi‐input single‐output converter that is based on the impedance network and the standard isolated converters is presented. The topology is named quasi Z‐source full‐bridge isolated converter (qZSFBIC). The proposed topology helps to integrate various renewable power generation systems with a common three‐phase grid‐connected inverter. It was also capable of providing isolation between the input and output circuits in addition to the boost function. The integration of multiple energy sources is achieved using fewer components than conventional converters. As a result, it achieves greater conversion efficiency and has improved circuit characteristics. It offers a larger voltage control range as compared to the conventional ZSC and enhances the input‐output voltage transformation ratio. To determine whether or not the suggested converter is technically feasible, the circuit architecture, operating principle, control mechanism, and simulation results are presented. An improved proportional resonant‐second order general integrator (IPR‐SOGI) has been utilized to provide a gating signal for the voltage source inverter. The 1.5 kW, 400 V, 50 Hz model is designed to authenticate the proposed scheme with qZSFBIC. The results showed that the proposed converter offered double the time of boosting than the conventional ZSC converter and the conversion efficiency is around 89%.

Analysis and Control of Impedance Network Integrated High Voltage Gain USMC for Wider Output Frequency

Analysis and Control of Impedance Network Integrated High Voltage Gain USMC for Wider Output Frequency

A Family of Single-Phase Buck-Boost AC-AC Converters Based on Impedance Network Cells With Reduced Active Switches

A Family of Single-Phase Buck-Boost AC-AC Converters Based on Impedance Network Cells With Reduced Active Switches

Dual-Wideband Rectenna for RF Energy Harvesting from 5G and WIMAX

ABSTRACT A dual wideband rectenna has been built to effectively capture radio frequency (RF) energy from 3.3 GHz to 3.7 GHz and 4 GHz to 6.3 GHz. An antenna with a rhombus form is created, which includes a rhombus slot and two rectangular strip ground planes. The planned antenna has been planned specifically to receive signals between the 3.5 GHz and 5.5 GHz frequency ranges. The highest conversion efficiency (CE) attained at 3.5 GHz and 5.5 GHz, without an impedance matching network (IMN), are 32.5% and 33%, respectively. These values are relatively low. To improve conversion efficiency, a two-line pi-impedance matching network is used, which includes DC combining. The rectenna is being evaluated for the specified frequency ranges. The highest simulated CE attained at 3.5 GHz was 81.5%, but the measured CE was 80% when the IPL was 3 dBm. The highest simulated CE at 5.5 GHz was 66.3%, but the measured CE was 65% when the IPL was 8 dBm. The proposed work is on the extraction of RF energy from the widely used 5 G and WiMax frequency bands.

Single‐stage single‐phase multiport DC–AC inverter suitable for standalone applications due to its notable performance in different operation modes

AbstractA new multiport DC–AC converter is proposed for standalone and off‐grid tied applications. The configuration converts power from DC to AC form in a single stage with suitable voltage gain. To increase the certainty of supporting power, the converter is designed to operate in four modes, including battery‐alone mode. The other advantage of the presented work is supplying the output power during unbalanced voltage conditions of the input ports. The advanced features of the converter for being used in standalone applications are related to the suitable placement and structure of the bidirectional port. In addition, the configuration is designed in a way to contain appropriate structural properties such as the existence of a common ground between the DC section and inverter, continuity of input currents, configured by an acceptable number of components, and low‐voltage stress on the DC–DC section's switches. Furthermore, it has an impedance network to protect the inverter's switches in a shoot‐through state. To confirm the converter advantages from the mentioned points of view, it has been compared with similar configurations. A prototype rated at 110 V is prepared to demonstrate the advantages of the converter performance per different conditions. The results of the steady‐state and transient experiments validate the suitability of the presented converter.

Self-Adaptive Resonance Technology for Wireless Power Transfer Systems to Eliminate Impedance Mismatches

Impedance mismatching can severely decrease the power transmission capacity or even invalid the control logic of wireless power transfer (WPT) systems. To eliminate the impedance mismatch caused by various factors, such as resonant parameter drift, coupling structure misalignment and control strategy, a self-adaptive mistuning correction circuit and corresponding parameter design rules are proposed to ensure the WPT system consistently operates under resonant state, accompanying the optimal power transfer ability. Moreover, a reactive compensation circuit that can create an auxiliary voltage source by the absorbed reactive power that is introduced by impedance mismatching is designed. This source can generate a new current on the coil to bring the mismatched input current back to the resonant state, according to the current superposition principle. Unlike passive impedance network that require high parameter precision and active impedance matching strategies equipped with detection and control circuits, the proposed approach can self-adaptively eliminate either undesired capacitive or inductive reactance with two additional switches and an energy-storage capacitor, improving impedance adjusting rate and providing better system robustness. The simulations and experiments are in good agreement with the theoretical analysis. This study has potential applications in harsh environments where the system impedance and coupling strength are continuously disturbed.

Single-point calibration process based integrated electrical impedance analyzer for multi-selective gas detection

Impedance analysis is a powerful technique that has become increasingly important in various applications, it represents a leap forward in the field of electronic measurments and diagnostics. In this work, we present the development of miniaturized, multiplexed, and connected platform for impedance spectroscopy. Designed for online measurements and adapted to wireless network architectures, our platform has been tested and optimized to be used for multi-selective chemical organic sensor nodes. This compact and versatile circuit is built from low cost and low power consumption (250 mW) microelectronics components that achieve long duration operability (5 days and 16 h) without compromising on sensor measurement accuracy and precision. We used the well-known impedance network analyzer AD5933 (Analog Devices, Norwood, MA, USA) chip which can measure a spectrum of impedances in the range 5 kHz to 100 kHz. The proposed system is based on ESP32-C3 Microcontroller enabling the management of the AD5933 through its I2C interface. Our system benefits from two multiplexer components CD74HC4067 allowing calibration process and the interface of 15 conductimetric sensors with real time acquisition (less than 90 ms per acquisition). The system is capable of relaying information through the network for data analysis and storage. The paper describes the microelectronics design, the impedance response over time, the measurement’s sensitivity and accuracy and the testing of the platform with embedded chemical sensors for gas classification and recognition.

A quasi-harmonic voltage compensation control of current-controlled battery energy storage systems for suppressing mid-frequency oscillations and harmonics

In grid-connected mode, current-controlled battery energy storage systems (BESS) face the issues of harmonic caused by nonlinear loads and interactive instability under weak grids. Firstly, the mechanisms of mid-frequency oscillations (MFO) and mid-frequency harmonics (MFH) are revealed by the impedance network theory and the circuit principle. Because harmonic currents of nonlinear loads tend to interact with the mid-frequency impedance of BESS to produce harmonic voltage drops, the grid is susceptible to MFH. Worse still, the grid-connected system based on BESS tends to exhibit negative damping characteristics in the mid-frequency band as the grid stiffness decreases, which triggers MFO. Aiming at the above problems, this paper proposes a quasi-harmonic voltage compensation control strategy without any harmonic extractor and provides a detailed parameter design rule. The proposed control strategy can effectively suppress MFO by enhancing the damping between BESS and weak grids. Meanwhile, the disturbance resistance of BESS to nonlinear loads is significantly improved because the impedance magnitude of BESS in the mid-frequency band is obviously reduced. Finally, the effectiveness of the proposed strategy is verified by simulation and experiment.

Laser irradiation induced CoNi@carbon composites as high-performance microwave absorbers

Metal-organic-frameworks (MOFs) derivatives, known for their lightweight and high-performance properties, are highly sought after as microwave absorbers. However, most reported MOFs derived absorbers are pyrolyzed in tube furnaces, which is time-consuming and difficult to finely tune the microstructure due to the low heating-quenching process. In this study, laser irradiation was used as a heat source to pyrolyze CoNi ZIF. By controlling the irradiation power (30 mW, 50 mW), Co/C composites were obtained in just a few seconds, with Co nanocrystals ranging from 10 to 50 nm. The presence of Ni could modulate the microstructure and electric-magnetic parameters of Co/C composites. The effects of Ni content and irradiation power on the electromagnetic absorption properties of Co/C were analyzed. Considering the enhanced dipolar/interfacial polarization, matched impedance, and strong magnetic coupling network, a minimum reflection loss of −45 dB with the effective absorption bandwidth of 6 GHz can be achieved by Co/C at the thickness of 2 mm. Additionally, the laser irradiation was performed in air atmosphere, providing an effective way for industrial production of high-efficiency and broadband wave-absorbing materials.

IEZ-Source Inverter Topology with Tuned PID Controller of Carrier SPWM Technique in Grid Connected System

Z-source inverters are used in controller applications, which offer higher performance than the buck-boost converter. This work presents the Improved Embedded Z (IEZ)-source inverter used for the impedance network. The Z-source inverter includes the switching topologies, so the double inductor is added to the EZ source inverter circuit. IEZ source inverter manages the Total Harmonic Distortion (THD), and the PID controller controls the inverter voltage. The Social Ski Driver (SSD) Optimization algorithm is used to tune the parameters of the PID controller. The harmonic content of the Z-source inverter is reduced by the carrier based sinusoidal Pulse Width Modulation (SPWM) technique. The Improved Embedded Z-source Inverter (IE-ZSI) is utilized to apply a grid-connected system. The inverters receive the power from the DC voltage and supply the grid-connected load with controllable voltage. The proposed work is implemented in the platform MATLAB/SIMULINK to evaluate the performance of the voltage across the capacitor, the voltage across the inductor, grid current and grid voltage. Inverter DC link voltage performance was compared to conventional Z-source inverters and embedded Z-source inverters. The proposed work achieved 1.52% THD compared with existing techniques.

Method for determining the harmonic contribution of consumer installations based on the application of passive filters

AbstractThe paper presents a new method for estimating the contribution of distortion sources based on the application of passive harmonic filters. The method does not require the measurement of harmonic network impedance and is based on the measurement of harmonic currents of the grid, consumers and passive harmonic filters. Evaluation of the consumer contribution using a passive harmonic filter is necessary to select the parameters and connection points for harmonic reduction devices. A feature of the method is the correct determination of share contributions, regardless of background harmonic distortions. Based on this method, a single consumer can evaluate both the harmonic contributions of its own loads, even in the presence of background distortions, and the harmonic voltage distortions in the case of installing harmonic reduction devices. The research results are confirmed in laboratory conditions with various combinations of electrical loads connected both at the grid side and at the consumer side. For such conditions, the proposed method was compared with existing methods, among which are methods based on the measurement of harmonic voltage vectors, harmonic current vectors and active harmonic power. The application of the developed method was demonstrated using the example of a gas production field.

High-performance passive impedance network model for grid-tie inverters in steady state

Nowadays, the high penetration of inverter-interfaced distributed energy resources (DERs) has raised a well-founded concern regarding the interaction of these devices with the upstream grid. The harmonic interaction phenomenon between these players can be described by time-domain simulations, using high computational effort switched and/or average models often impractical for large power systems. This paper proposes an innovative low-computational-burden model named passive impedance network (PIN), capable of accurately representing DERs in electric power systems (EPSs). Through passive RLC components, the PIN model can describe DER dynamic behavior at a certain frequency of interest, making it able to represent harmonic flow within the EPS nodes. The proposed model is compared with the switched model, average model, and an experimental setup under different grid distortions and injected current profiles. A comparison of the total demand distortion (TDD) between the proposed PIN model and the experimental results is carried out. The effect of DER parameter deviations on PIN model accuracy is addressed, in which the absolute error of the PIN model TDD values are 0.65% and 0.06% for the experimental and switched model, respectively. Besides, the PIN model presents an improved computational performance compared to the time-domain-based switching model, requiring 99% less computational burden.