Common Ground Structure Research Articles

A novel asymmetric antipodal Vivaldi MIMO antenna

This communication describes the development and assessment of the genuine Antipodal Vivaldi MIMO antenna operating in the ultra-wideband spectrum. FR4 dielectric material, which is widely used in antenna designs and has characteristic features, is selected and used as a dielectric. The single antenna component has two asymmetric flares obtained with different parameters, and it also has a rectangular ground plane combined with a bottom flare. In the MIMO configuration, the single-antenna is built in a rotationally orthogonal way to generate a four-port system with the dimensions of 45 × 45 × 1 mm3. The vertical and horizontal stubs are added to the ground flare to obtain a common ground structure and increase the performance of the novel antenna design. It has a bandwidth of approximately 9 GHz, which starts from 2.85 GHz and ends at 11.8 GHz. The antenna has reasonable gain values and a high isolation value between the elements in the operation range. In this context, it is foreseen that the developed structure can be utilized in distinct multiport UWB applications.

Self-Balanced Switched-Capacitor Common-Grounding Boost Multilevel Inverter

Transformerless inverters have been extensively deployed in photovoltaic (PV) applications, owing to features such as high efficiency, high power quality, and low cost. However, the leakage current in such inverters due to the absence of galvanic isolation has resulted in several topological modifications. This paper introduces a single-input switched-capacitor (SC)-based multilevel inverter (MLI) that is capable of eliminating the leakage current due to its common-ground structure. Also, the proposed inverter has the capability of single-stage voltage boosting, which is essential in PV systems. The series–parallel switching facilitates the self-balancing of SCs, which, in turn, assists in voltage boosting. Moreover, the proposed MLI synthesizes a seven-level output using only eight switches. Following an in-depth analysis of the circuit operation, modulation scheme, and power losses, a detailed comparison among recently developed seven-level MLIs is carried out, which verifies the design's superiority. Extensive simulation and experimental results are presented to validate the prominent features of the seven-level MLI under dynamic operating conditions.

Synchronous Dual-Switch Ultrahigh Step-Up DC–DC Converter Based on Coupled Inductor and Voltage Multiplier for Photovoltaic Systems

In this article, an ultrahigh step-up quadratic boost converter is proposed for photovoltaic systems. By integrating with a coupled inductor and a voltage multiplier, the voltage gain can be improved significantly without high turns ratio and the voltage stress across the power switches are alleviated. Thus, low on-resistance of the power switches are available to enhance efficiency. Common ground structure of quadratic boost and synchronous operation of the two switches facilitate the control. Also, the continuous input current promotes the maximum power point tracking (MPPT). Detailed description of the operation principles and steady-state analysis of this converter in CCM and DCM are presented. A 250W rated laboratory prototype is fabricated and verified, demonstrating a maximum efficiency of 96.5%. Moreover, the dynamic response is tested to prove the stability of the proposed converter. Finally, a simulation is built to evaluate the feasibility of MPPT function.

Compound reconfigurable symmetric slotted mimo antenna with abs enclosure for indoor wireless applications

This research work reports the Compound Reconfigurable MIMO Antenna (CRMA) utilizing RF PIN diodes for indoor wireless communication applications. The proposed CRMA comprises a quad-symmetric Slotted Radiator (SSR) with a common ground structure. It can perform frequency, polarization and pattern switching at frequency standards such as IEEE 802.11a/b/g/n (2.4/5.5 GHz), IEEE 802.11ax (6 GHz) and 5G/n78 (3.5 GHz). A parasitic element of a modified U-shaped stub is utilized to achieve polarization reconfiguration. Further, to achieve pattern reconfiguration two crossed-shaped slots are implemented. The proposed antenna achieves a bandwidth of 320 MHz at 2.4 GHz, 950 MHz at 3.5 GHz and 1870 MHz at 5.5 GHz. At these resonant frequencies, the antenna is capable of producing both circular and linear polarization with a pattern tilt towards different angular directions such as 30°, 120°, 210°, 300°, 330°, 240°, 150°, 60°. The designed CRMA follows orthogonal orientation and exhibits better diversity performance with ECC < 0.1, DG > 9 dB, TARC < -13 dB and CCL < 0.27 bps/Hz. Also, an Acrylonitrile Butadiene Styrene (ABS) enclosure is designed and fabricated to validate the performance of the antenna with casing, further to analyze the suitability of the antenna for indoor wireless applications

A NOVEL HIGH-GAIN DC-DC CONVERTER APPLIED IN FUEL CELL VEHICLES

Fuel cell cars should have DC-DC converters with high efficiency, low voltage stress, small size, and high gain. Nevertheless, the requirements are not met by traditional two-level, three-level, or cascaded boost converters. In this work, a novel non-isolated DC-DC converter with switched capacitor and switched inducer is proposed. The proposed non-isolated DC-DC converter exhibits a common ground structure, ensuring high gain, a broad input voltage range, and minimal voltage stresses across components. The comprehensive study includes an analysis of component parameters, the elucidation of the working principle, and thorough comparisons with other high-gain converters. To establish a dynamic model, the small-signal modeling approach and state-space averaging method are employed. Experimental and simulation data affirm that the suggested structure performs as intended. The experimental prototype operates within an input voltage range of 25V to 80V, featuring a rated output voltage of 200V and a rated power of 100W. The converter achieves its most efficient state at 93.1%, an aspect that may be underappreciated. Importantly, the recommended converter is deemed suitable for fuel cell vehicles, offering a promising solution to address their unique requirements.

Single‐phase five‐level common‐ground transformerless inverter using switched capacitors for photovoltaic application

AbstractTransformerless inverters (TLIs) are extensively used in the photovoltaic (PV) grid‐connected system. TLI with a common ground structure exhibits multiple excellent features that improve the efficiency of the inverter, eliminating leakage current and boosting the voltage. The use of TLI eliminates the electrical isolation required between PV and the grid, resulting in a leakage current (LC) issue. The LC affects the power quality of the inverter and creates a safety‐related issue. This paper presents a new TLI topology based on the common ground (CG) structure. This topology uses eight switches and two self‐balanced switched capacitors. Phase disposition pulse width modulation (PD‐PWM) control scheme is used to create a five‐level output voltage. Further, adequate analysis for component selection and loss analysis is carried out to evaluate the efficiency. Its CG configuration certifies that there is minimal LC and common mode voltage (CMV). It also supports the active and reactive power of the grid. Its dual gain makes it suitable for photovoltaic (PV) applications. This topology is simulated for leading, lagging, unity power factor (UPF), and changes in input voltage and load conditions. Later, a corresponding experimental test is carried out on a laboratory prototype (1 kW). An equitable comparison is carried out for the component, stresses, and features like CG, and LC, along with efficiency.

Switched inductor‐capacitor‐based quasi‐Z source converter for renewable energy source integration

SummaryIn applications involving renewable energy sources such as solar PV and fuel cells, the high‐gain DC–DC converter must have the following desirable characteristics: high voltage gain, continuous input current with low ripple content, common ground structure, reduced voltage stress on the components, and high efficiency. In addition, the requirement of a lower duty ratio to produce a higher voltage gain aids in reducing the converter's inductor core saturation issue. In this research, a converter employing switched capacitor–inductor cells and a quasi‐Z source network with the aforementioned features is proposed. The steady‐state analysis in both CCM and DCM is presented. The performance of the converter including the parasitic effect of converter components is analyzed. This paper also includes a comprehensive comparative analysis highlighting the benefits of the proposed converter. A small signal model and the output‐to‐control transfer function are derived. The analytical performance of the proposed converter is validated using a hardware prototype of 500 W, 50 kHz. A compensator is designed to improve the dynamic closed‐loop performance and validated experimentally. The experimental findings for boosting 48 V input to 650 V output are provided. The results prove that the proposed converter has the advantages of high gain with a lower duty ratio, low voltage stress on components, continuous input current with low ripple content, and a common ground structure.

Common Grounded Wide Voltage-Gain Range DC–DC Converter With Zero Input Current Ripple and Reduced Voltage Stresses for Fuel Cell Vehicles

A dc–dc converter used for fuel cell vehicles should be characterized by a wide voltage-gain range and low input current ripple. In order to meet the above requirements, a new nonisolated dc–dc converter consisting of an active switched-inductor cell, a zero current ripple cell, and a switched-capacitor (SC) cell was proposed in this article. The proposed converter integrates with the advantages of a wide voltage-gain range, zero input current ripple, low voltage stresses across power semiconductors, and common ground structure. Thanks to the use of a zero current ripple cell, not only the input current ripple is reduced but also the energy transfer path of the SC cell is changed, thereby reducing the instantaneous peak current of the SC structure. The operating principles, the characteristics analysis, and the parameter design of the proposed converter are given. In addition, to show the merits of the proposed converter, a comparison study is demonstrated. Finally, a prototype of 400 V, 1000 W/50 kHz is developed to validate the effectiveness of the proposed converter.

Dual-Ground Transformerless Nine-Level Dynamic Voltage Boosting Inverter Topology

ABSTRACT This article presents a new nine-level common ground (CG) type transformerless inverter (TL) structure with an integrated boost (IB) cell. The proposed structure eliminates the leakage current due to the CG structure between the input source and the grid neutral. The proposed topology is derived by combining a DC-DC boost converter and switched capacitor (SC) cell, capable of generating the nine-level output voltage over a wide range of input voltage variations. By maintaining the duty cycle of the IB converter switch at 50%, the proposed topology generates the output voltage with a boosting factor of 4. Besides, soft charging of the involved SCs and reduced inrush current is also achieved through the inductor, which ensures the permissible current stresses of the power switches. Furthermore, the voltage across the SCs is self-balanced, eliminating the need for complex independent control techniques. A 725-W laboratory prototype is built to test the performance of the proposed topology under various operating conditions, such as input and load variations. The measured efficiency of 96.9% at 725 W is obtained and is comparable with the simulation efficiency. Finally, the merits of the proposed topology are highlighted using a detailed comparison with the other recent nine-level inverter topologies.

A Novel Single-Stage Common-Ground Zeta-Based Inverter With Nonelectrolytic Capacitor

Aiming at the key problems of the existing nonisolated photovoltaic (PV) inverter, such as the common mode (CM) leakage current, the voltage up and down ability, and the service life restricted by the electrolytic capacitor, a novel single-stage common-ground zeta-based inverter with nonelectrolytic capacitor is proposed in this article. The proposed inverter is based on zeta dc converter and has the inherent voltage conversion characteristics of zeta converter, which makes it more suitable for PV system with wide input voltage fluctuation range. In addition, common-ground structure is adopted in this inverter, which can shorten the parasitic capacitor of the PV array to the ground. Therefore, it can effectively suppress the CM leakage current, reduce the shutdown frequency of the PV system, and improve the utilization rate of solar energy. Moreover, the proposed inverter does not contain electrolytic capacitors, which avoids the problem of high maintenance cost due to the short service life and high equivalent series resistance of electrolytic capacitors. First, the topology of the proposed inverter is given, and the modulation and operating principle are analyzed. Second, the passive components are analyzed. Finally, a 1 kW prototype is built for experimental verification. The experimental results verify the correctness of the theoretical analysis and simulation.

A Non-Pulsating Input Current Step-Up DC/DC Converter With Common Ground Structure for Photovoltaic Applications

Many of the High Gain Step-Up DC/DC converters proposed in the literature do not share common ground and have a pulsating or discontinuous input current, making the converter unsuitable for solar photovoltaic applications. In this article, a non-pulsating input current (NPIC) with a high-gain DC/DC step-up converter is proposed and analyzed in detail. The converter shares a common ground structure and a voltage conversion ratio more than twice that of the Traditional quadratic boost converter (TQBC). The converter has two switches that operate in phase, which makes it easy to control. Also, the voltage stress across all semiconductor devices is lower than the output voltage, which enhances the efficiency of the converter. The loss analysis is carried out with the PLECS software, integrating the real models of switches and diodes from the technical datasheet. To confirm and validate the functionality of the proposed converter, a 200 W hardware prototype is being developed in the laboratory. It was observed that the maximum efficiency was 94.5% with an input voltage of 16V. The converter achieves high gain at low duty cycles and has been shown to perform well in open loop conditions.

A Novel High-Gain DC-DC Converter Applied in Fuel Cell Vehicles

The DC-DC converter for fuel cell vehicles should be characterized by high-gain, low voltage stress, small size and high-efficiency. However, conventional two-level, three-level and cascaded boost converters cannot meet the requirements. A new non-isolated DC-DC converter with switched-capacitor and switched-inductor is proposed in this paper, which can obtain high-gain, wide input voltage range, low voltage stresses across components and common ground structure. In this paper, the operating principle, component parameters design, and comparisons with other high-gain converters are analyzed. Moreover, the state-space averaging method and small-signal modeling method are adopted to obtain the dynamic model of converter. Finally, simulation and experimental results verify the effectiveness of the proposed topology. The input voltage of the experimental prototype ranges from 25 V to 80 V. The rated output voltage is 200 V and rated power is 100W. The maximum efficiency is 93.1% under rated state. The proposed converter is suitable for fuel cell vehicles.

Design, Control, and Analysis of a Novel Grid-Interfaced Switched-Boost Dual T-Type Five-Level Inverter With Common-Ground Concept

Multilevel inverters with a common-ground structure and voltage step-up feature are beneficial for transformerless grid-connected photovoltaic applications. In this article, a novel topology of such converters with a five-level output voltage generation is presented. The proposed topology comprises of an integrated switched-boost (SB) module and a dual T-type (D2T) cell constructed with 10 power switches (six unidirectional and two bidirectional). An inductor in the integrated SB module is used to boost the voltage across two involved capacitors of the D2T cell. Therefore, a desirable ac voltage magnitude for the grid-connected application can be achieved over a wide range of input voltage changes. Current stress is also kept within a permissible input current range by the soft-charging operation of the involved capacitors through the inductor. A corresponding dead-beat continuous-current-control-set controller with a sinusoidal PWM modulator is implemented for controlling the real and reactive powers. The controller has an added benefit of achieving constant switching frequency for power switches. Circuit description, theoretical analyses, and comparative study are discussed. Simulation and experimental results are also presented to confirm the feasibility and correctness of the proposed topology.

A Common-Ground Quazi-Z-Source Single-Phase Inverter Suitable for Photovoltaic Applications

In this article, a coupled inductor common-ground single-phase inverter, well-suited for photovoltaic (PV) applications, is presented. The proposed PV inverter is constructed based on a two-stage topology. At the first stage, a high gain DC-DC structure converts low PV voltage to the high bipolar output voltages. The produced bipolar output voltages are the inputs for the conventional half-bridge inverter in the second stage. It is noteworthy that the parasitic capacitors between the PV panel and its ground provide the path for circulating the leakage current in conventional configurations. This problem is tackled in the proposed topology by making a common-ground structure. Furthermore, the first stage contains only one switch with low voltage stress, which leads to a significant suppression in conduction losses. The proposed DC-AC structure has the ability to reduce the input current ripple and also recycle the leakage energy caused by the coupled inductor. The operation principles of the proposed structure are analyzed in detail, and finally, the experimental results are accomplished to confirm the accuracy of the performed analysis.

A Low-Current Ripple and Wide Voltage-Gain Range Bidirectional DC–DC Converter With Coupled Inductor

In this paper, a bidirectional dc–dc converter with coupled inductor is proposed. The proposed converter can achieve a wide voltage-gain range by turning the ratios of windings of the coupled inductor. Furthermore, the voltage stresses across the power switches are reduced. By employing a low-current ripple structure, a tiny input/output current ripple can be achieved, which can avoid larger filters. In addition, the common ground structure between the grounds of the input and the load sides can avoid extra d u /d t issues. A prototype rated at 400 W/300 V has been developed and the maximum efficiency of the proposed converter was measured as 94.2%. Experimental results are presented to validate the effectiveness of the proposed converter.

5.8 GHz High-Efficiency RF-DC Converter Based on Common-Ground Multiple-Stack Structure.

This paper presents a 5.8 GHz RF–DC converter for high conversion efficiency and high output voltage based on a common-ground and multiple–stack structure. An RF isolation network (RFIN) for the multiple-stack RF–DC converter is proposed to combine the DC output voltage of each stack without separating its RF ground from the DC ground. The RFIN is designed using micro-strip transmission lines on a single-layer printed circuit board (PCB) with a common ground for the bottom plate. A 4-stack RF–DC converter based on a class-F voltage doubler for each stack was implemented to verify the proposed RFIN for the multiple-stack and common-ground structure. The performances of the implemented 4-stack RF–DC converter were evaluated in comparison to the single-stack converter that was also implemented. The size of the implemented 4-stack RF–DC converter using bare-chip Schottky diodes is 24 mm × 123 mm on a single-layer PCB. For an input power of 21 dBm for each stack of the RF–DC converter with a load resistance of 4 kΩ, a high efficiency of 73.1% and a high DC output voltage of 34.2 V were obtained.

Design for Triple Band Patch Array Antenna with High Detection Ability

This paper proposes a theoretical analysis of hidden device detection and a design of multiband circular polarization patch array antenna for non-linear junction detector system application. A good axial ratio of circular polarization patch antenna is realized by a new approach that employs inclined slots, two rectangular grooves and a truncated ground for the conventional antenna. A good axial ratio of the 1.5 dB lower is measured by having an asymmetric gap distance between the ground planes of the coplanar waveguide feeding structure. The common ground plane of the linear array has an optimum trapezoidal slot array to reduce the mutual coupling without increasing the distance between the radiators. The higher gain of about 1 dBi is realized by using the novel common ground structure. The measured return loss, gain, and axial ratio of the proposed single radiator, as well as the proposed array antennas, showed a good agreement with the simulated results.

The obligations and common ground structure of practical dialogues

In this paper a theory of dialogue structure of tas k oriented conversations and its associated tagging scheme are presented. The theory introduces two linguistic str uctures supporting the dialogue that, following tra ditional terminology, we call the obligations and common ground. The theory is illustrated with the detailed an alysis of a transaction. We also describe the empirical work su pporting the theory, as well as an evaluation task. The paper is concluded with a reflection on the relation of the present theory to traditional notions of obligation s and grounding, its relation to a more general theory of discourse and conversation and its potential application to t he construction of spoken natural language systems.