Dual-mode Operation Research Articles

Streamlining the supply chain for the future of world energy - VALYNT secures contract with ESSCO to provide Saudi Aramco with proprietary chemicals related to production and refining of petroleum products

This chapter aims to present several modelling approaches to analyze energy systems that implement a particular category of fuel cells and electrolyzers, namely reversible Solid Oxide Cells (rSOCs). This technology allows the dual operation mode, hence requires particular care in the analysis of processes, transient operation and energy/power management in the long-term. Therefore, this chapter reviews the principal methodologies adopted to the scope.

A 32-Gb/s Dual-Mode Transceiver With One-Tap FIR and Two-Tap IIR RX Only Equalization in 65-nm CMOS Technology

This article presents an receiver (RX) only equalization (ROE) technique that eliminates feed-forward equalization (FFE) in transmitter (TX) and bandwidth improved output driver without increment of power consumption. With a help of the proposed design technique, the power consumption, circuit complexity, and design cost are improved. The proposed RX with one-tap finite-impulse response (FIR) and second-tap IIR decision feedback equalizer (DFE) removes the FFE equalization in TX by moving the sampling point of main cursor in the received data. A simpler TX architecture with nMOS only output driver (NOD) owing to the ROE facilitates a wide bandwidth and energy efficient dual-mode (differential and single-ended) operation. The proposed transceiver was fabricated in a 65-nm CMOS technology. The RX achieves bit error rate (BER) less than 10^{-12} over a 22-dB channel loss at 32 Gb/s with 0.62-pJ/bit energy efficiency, and the TX with NOD has 0.77- and 0.40-pJ/bit energy efficiency at 32 Gb/s in differential mode and single-ended mode, respectively. The occupied area of TX and RX is 0.002 and 0.024 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , respectively.

Dual-Mode Power Operation for Grid-Connected PV Systems with Adaptive DC-link Controller

Photovoltaic (PV) power systems are integrated with high penetration levels into the grid. This in turn encourages several modifications for grid codes to sustain grid stability and resilience. Recently, constant power management and regulation is a very common approach, which is used to limit the PV power production. Thus, this article proposes dual-mode power generation algorithm for grid-connected PV systems. The developed system considers the two-stage PV configuration for implementation, where the dual-mode power generation technique is executed within the DC–DC conversion (boost) stage. Most of the techniques adopted for dual-mode power operation employ the conventional perturb and observe method, which is known with unsatisfactory performance at fast-changing atmospheric conditions. Considering this issue, this study suggests a modified maximum power point tracker for power extraction. Furthermore, a new adaptive DC-link controller is developed to improve the DC-link voltage profile at different operating conditions. The adaptive DC-link controller is compared with the traditional PI controller for voltage regulation. The inverter control is accomplished using finite-set model predictive control with two control objectives, namely reference current tracking and switching frequency minimization. The overall control methodology is evaluated at different atmospheric and operating conditions using MATLAB/Simulink software.

A Dual-Mode InGaP/GaAs HBT Power Amplifier Using a Low-Loss Parallel Power-Combining Transformer with IMD3 Cancellation Method

A dual mode InGaP/GaAs heterojunction bipolar transistor (HBT) power amplifier (PA) using a parallel power-combining transformer (PCT) is presented herein. A low loss transformer is implemented on a printed circuit board (PCB) to improve the passive efficiency of a PCT. Dual-mode operation is applied to reduce the current consumption at a low power level. In the low-power (LP) mode, one of the individual amplifiers is turned off to reduce the current consumption. Additionally, a third-order intermodulation distortion (IMD3) cancellation method using a PCT combiner is proposed to improve linearity performance. Nonlinear IMD3 components from each amplifier cancel each other out through magnetic coupling in the secondary winding of the PCT. The implemented PA achieves a saturated output power of 33.8 dBm and a peak power-added efficiency (PAE) of 54.5% at 0.91 GHz with a 5-V power supply. An average output power of 25.2 dBm with an adjacent channel leakage ratio (ACLR) of −42 dBc is delivered when the PA is tested with an orthogonal frequency division multiplexing (OFDM) 64-quadrature amplitude modulated (64-QAM) signal with a bandwidth of 10 MHz and peak-to-average power ratio (PAPR) of 7.8 dB. When compared with the high-power (HP) mode operation, the LP mode operation could save 48% of the current consumption at an average output power of 10.4 dBm.

All-Electrical High-Sensitivity, Low-Power Dual-Mode Gas Sensing and Recovery with a WSe2/MoS2 pn Heterodiode.

Two-dimensional MoS2 gas sensors have conventionally relied on a change in field-effect-transistor (FET) channel resistance or in the Schottky contact/pn homojunction barrier. We demonstrate an enhancement in sensitivity (6×) and dynamic response along with a reduction in detection limit (8×) and power (104×) in a gate-tunable type-II WSe2(p)/MoS2(n) heterodiode gas sensor over an MoS2 FET on the same flake. Measurements for varying NO2 concentration, gate bias, and MoS2 flake thickness, reinforced with first-principles calculations, indicate dual-mode operation due to (i) a series resistance-based exponential change in the high-bias thermionic current (high sensitivity), and (ii) a heterointerface carrier concentration-based linear change in near-zero-bias interlayer recombination current (low power) resulting in sub-100 μW/cm2 power consumption. Fast and gate-bias tunable recovery enables an all-electrical, room-temperature dynamic operation. Coupled with the sensing of trinitrotoluene (TNT) molecules down to 80 ppb, this study highlights the potential of the WSe2/MoS2 pn heterojunction as a simple, low-overhead, and versatile chemical-sensing platform.

Study on dual-mode large-mode-area multi-core fiber with air-hole

In this paper, a multi-core fiber with 22 air holes and 15 conventional cores is proposed. The fiber can realize dual-mode operation of fundamental mode HE11 and second-order mode HE21 under certain conditions. The relationship between performance of the fiber and the structural parameters that include core pitch, refractive index difference between core and cladding, and fiber core radius is investigated systematically. By adjusting the above parameters, the effective area of fundamental mode can be up to 1423.972 µm2 and keep a low bending loss at 1550 nm. Due to its flexibility of the structure, the proposed fiber is significant for theoretical research and practical manufacturing.

Design and fabrication of a modified fish feed pelletizing machine

Fish feed pelletizing machine was designed and fabricated with the aim to improve on existing local pelletizers; encourage local technology and local fish farmers who may be faced with no power supply. It mainly consists of the hopper, pelletizing chamber, frame, bolts and nuts, screw conveyor, cutting mechanism, pelletizing die plate and power transmission unit with dual operation mode. Performance evaluations of the improved pelletizing machine as well as existing machine were carried out and the results showed that both machines were able to produce pellets with 8 mm average diameter and 10 mm average length. The overall mean values of pelleting capacity, specific energy consumption and efficiency of improved and the existing pelletizing machines were 1.20 kg/min, 0.010 kWh/kg and 97.09%; 0.89 kg/min, 0.014 kWh/kg and 75%, respectively. These imply that the improved pelletizing machine could produce a ton of feeds for a 14-hour daily operation and consume approximately 10 kWh of energy as compared to the existing pelletizing machine that would consume 14 kWh. The capacity of the improved pelletizing machine is quite better than the existing pelletizing machine. The improved pelletizing machine efficiency obtained is quite impressive as only about 2.91% of the feed mix might be lost as compared to 25% lost by the existing pelletizing machine. Therefore, the improved fish feed pelletizing machine is recommended for use by small-scale fish feed mill as the existing pelletizers have comparable higher losses couple with lower efficiency.

A Symmetric Three Degree of Freedom Tensegrity Mechanism with Dual Operation Modes for Robot Actuation.

Tensegrity robots that use bio-inspired structures have many superior properties over conventional robots with regard to strength, weight, compliance and robustness, which are indispensable to planetary exploration and harsh environment applications. Existing research has presented various tensegrity robots with abundant capabilities in broad scenarios but mostly not focused on articulation and manipulability. In this paper, we propose a novel tensegrity mechanism for robot actuation which greatly improves the agility and efficiency compared with existing ones. The design integrates two separate tensegrity substructures inspired by shoulder and hip joints of the human body and features a similar form to a hexapod platform. It mitigates detrimental antagonistic forces in the structural network for optimising actuation controllability and efficiency. We validated the design both on a prototype and in a Chrono Engine simulation that represents the first physically accurate simulation of a wheeled tensegrity robot. It can reach up to approximately , and in pitch, yaw and roll motion, respectively. The mechanism demonstrates good agility and controllability as an actuated robot linkage while preserving desirable properties of tensegrity structures. The design would potentially inspire more possibilities of agile tensegrity implementations that enable future robots with enhanced compliance, robustness and efficiency without a tradeoff.

Biosupercapacitor with an enzymatic cascade at the anode working in a sucrose solution

In this report, we demonstrate the advantages of the dual-mode operation of an enzymatic biosupercapacitor with nanostructured polypyrrole/nanocellulose, gold nanoparticle-based paper electrodes, sucrose as the anode fuel and molecular oxygen as the oxidant. The device allowed conversion of the sucrose biofuel, and offered storage of the generated power in the same, small-scale device. The external and internal biosupercapacitor re-charging modes were compared. The specific capacitance of the device was 1.8 F cm−2 at a discharge current density of 1 mA cm−2. The cell used in the charge/discharge mode of operation allowed retention of 49% of the initial capacitance after eight days of exhaustive discharging under external load. The discontinuous capacitive mode, preserved the biocatalysts activity for much longer time. The use of such enzyme-based electrical energy sources in the capacitive mode i.e. under discontinuous charging was demonstrated as a solution for preserving high specific capacitance and long-term operational stability.

Dual-Mode Control for Brushless Doubly Fed Induction Generation System Based on Control-Winding-Current Orientation

Brushless doubly-fed induction generator (BDFIG) has huge potential due to its high reliability and low maintenance costs. In order to meet the requirements of the modern grid code, the BDFIG system should have dual-mode (i.e., operating in both stand-alone and grid-connected modes) capability. Rather than using two separated systems for two modes, this article proposes a unified control architecture for dual-mode operation. Such a unified architecture is based on the stand-alone control-winding (CW) current orientation, and the grid-connected functions are realized by adding three plug-in functional units: 1) the phase-lock function is realized by adding an increment adjustment controller into the CW-angle control; 2) the inrush current during mode switching is suppressed by adding a high-pass feedforward controller into the inner-loop controller; 3) the active power and reactive power are regulated by adding an amplitude-angle controller of CW current. With the proposed unified architecture, the high-performance dual-mode operation is achieved without breaking the original CW-current orientation system, facilitating the overall system design a lot. The detailed analysis and designs are given in this article, and the experiments based on a BDFIG prototype are given to verify the feasibility.

Adaptive anti-thermal imaging protection for moving objects

The paper provides a classification and outlines the current state of anti-thermal imaging protection of military equipment. Currently, improving the reliability of such objects in combat conditions is one of the key tasks. The authors carried out the analysis and considered the prospects for the development of existing systems of anti-thermal imaging protection for moving objects as an important factor in increasing their reliability. It has been shown that the most promising are active-type anti-thermal imaging protection systems. The paper proposes a way to improve the reliability of armored and other vehicles in modern conditions. As an example, an anti-thermal imaging protection system consisting of active cooling modules is considered for armored vehicles. It can operate in two modes: stealth and rapid supercooling of the object’s surface (“black hole”). During the operation of the anti-thermal imaging protection, the system uses controlled cooling of active modules with liquid nitrogen. A design is proposed and a method for calculating the parameters of active cooling modules is developed. The advantages of the developed anti-thermal imaging system for protecting the object are as follows: dual-mode operation of the system and the use of a pre-stored “cold” source, which makes it possible to eliminate the need for additional energy consumption during operation. The proposed system of modular active anti-thermal imaging protection can be used for different vehicles with appropriate adaptation to the object of the general design of the system and modification of the adjustable cooling active module.

Design of Frequency Conversion and Soft Start Cooperative Control System for Mine Fan

In order to improve the safety and reliability of mine fan control system and realize remote control in dual operation modes, a cooperative control system of frequency conversion and soft start of mine fan was developed based on PLC. On the basis of analyzing the position of coal mine in China’s economic development and the role of coal mine ventilation system, this paper expounds the working principles of mine soft starter and mine frequency converter, and designs a cooperative control system of mine fan frequency conversion and soft start based on PLC, which realizes remote control of mine fan starting, running and stopping, and has the functions of voltage, current, wind speed and air volume parameter monitoring and fault protection.

Terahertz dual-comb spectroscopy: A comparison between time- and frequency-domain operation modes

In terahertz dual-comb spectroscopies (THz-DCSs), electrical time delay lines are utilized to replace the mechanical ones widely used in traditional terahertz time-domain spectroscopic systems (THz-TDSs). Due to the usage of electrical delay line, the sampling time is effectively prolonged and the consecutive terahertz pulses can be sampled continuously, which leads to the improvement of frequency resolution and makes it possible for THz-DCSs work in dual (frequency- and time-domain, FD and TD) operation modes. Here, a THz-DCS is established by using two repetition-frequency-locked femtosecond (fs) lasers with a slight repetition frequency difference. A spectrum analyzer is used to directly record the terahertz spectral data. Alternatively, the terahertz transient pulses are sampled and recorded, and the terahertz spectra are obtained by Fourier transforming the TD data. The experimental results show that the terahertz spectra acquired in FD and TD are in good agreement with each other. For the dual-mode THz-DCS, the wideband terahertz spectral information and the specified narrowband spectral information with high frequency resolution can be simultaneously acquired, which is helpful for searching sharp-peaked fingerprint spectral features in a broad terahertz frequency range.

A Dual-Mode Continuously Scalable-Conversion-Ratio SC Energy Harvesting Interface With SC-Based PFM MPPT and Flying Capacitor Sharing Scheme

This article proposes a continuously scalable-conversion-ratio (CSCR) switched-capacitor (SC) energy harvesting interface that extracts power from a thermoelectric generator (TEG), regulates a 0.75-V output load, and manages a 1.2-1.45-V battery. The structure employs the proposed CSCR SC converter to improve the power conversion efficiency up to 7.9% higher than that of the conventional converter. Moreover, the structure utilizes a proposed SC-based pulse frequency modulation (PFM) maximum power point tracking (MPPT) method to extract power from a TEG with an MPPT efficiency above 98.15%. In addition, the proposed interface adopts a flying capacitor sharing scheme for the dual-mode operation of the SC interface to increase both the peak end-to-end efficiency and maximum output power. With a 180-nm CMOS process, the proposed interface achieves a peak end-to-end efficiency of 85.4% and maximum output power of 20.8 mW.

A Diamond Shaped Multilevel Inverter With Dual Mode of Operation

This study presents a novel multilevel inverter structure that can operate in both switched capacitor and asymmetric DC source modes. In the first mode, it can produce seven-level output voltage employing two switched capacitors and one single DC supply. The five-level output voltage is produced while operating the second mode. The voltage ratio between the input and output voltage for the capacitor mode is 1:3 (triple voltage gain). During the first mode, the capacitor of the inverter is self -balanced whereas the inverter can produce higher voltage output in the DC source mode. The proposed inverter reduces the total standing voltage in both modes of operations as it can generate the output voltage without requiring any additional H-bridge circuit. The feasibility and predominate features of the proposed inverter have been established by comparing with existing topologies in terms of power components count. Results obtained from this study are validated using simulation employing sinusoidal pulse width modulation (SPWM). A hardware prototype has also been developed for further validation.

FREQUENCY RECONFIGURABLE ANTENNA WITH DUAL-BAND AND DUAL-MODE OPERATION

FREQUENCY RECONFIGURABLE ANTENNA WITH DUAL-BAND AND DUAL-MODE OPERATION

Filtering Quasi-Yagi Strip-Loaded DRR Antenna With Enhanced Gain and Selectivity by Metamaterial

This paper presents a design approach of broadband filtering quasi-Yagi DRR Antenna using a strip-loaded dielectric ring resonator (DRR) and near-zero-index (NZI) metamaterial (NZIM). The ring strip is loaded to the inside wall of the DRR so that the TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01δ</sub> and TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21δ</sub> modes of the DRR can be close. Meanwhile, they function as a dual-mode magnetic dipole (M-dipole) driver and can be differentially excited at the same time for designing a wideband quasi-Yagi antenna. Benefiting from the dual-mode operation of the strip-loaded DRR, the end-fire gain across the operating band of the antenna is stable with preliminary bandpass filtering characteristics. To improve the in-band gain and enhance the filtering capability, a new coplanar NZIM with wideband NZI characteristic and dual transmission notches in the lower and upper stopbands of the preliminary gain passband, is introduced and put in the front of the DRR driver. To verify the proposed design concept, an X-band filtering quasi-Yagi antenna with the NZIM is fabricated and measured. Good agreement between the simulated and measured results can be observed. The wideband antenna has a measured -10 dB impedance bandwidth of about 16% (8.5 - 10 GHz). Within it, the peak gain of antenna reaches 8.3 dBi and 1-dB gain fractional bandwidth is about 10.8%. Meanwhile, it exhibits good gain bandpass response due to the transmission notches of the NZIM.

120-GHz Wideband I/Q Receiver Based on Baseband Equalizing Technique

In this study, we examined a 120-GHz wideband I/Q receiver based on a baseband equalizing amplifier using 40-nm complementary metal oxide semiconductor (CMOS) technology. For low-power operation, the receiver chipset is integrated based on the direct conversion structure. To achieve high data-rate wireless communication, the receiver utilizes a frequency equalizing technique between the low noise amplifier (LNA)-mixer and baseband amplifier. With the proposed technique, the estimated overall bandwidth is increased as wider as 5 GHz. The 3-dB conversion gain bandwidth is 26 GHz, noise figure (NF) is 10.8 dB, and dc power consumption is 153.4 mW. For the dual-mode operation, the variable gain of the baseband amplifier is applied, and the conversion gain of the proposed receiver is 28.2 dB for the high gain mode and 14.8 dB for the low gain mode. The chip area of the receiver is 1.5 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The proposed receiver exhibits a maximum data-rate of 12.5, 16, and 16 Gb/s for binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), and 16-quadrature amplitude modulation (16-QAM), respectively.

An Asynchronous Boost Converter With Time-Based Dual-Mode Control for Wide Load Range and High Efficiency in SSD Applications

A highly integrated, high-voltage dual-mode boost converter is presented for solid-state drives applications in portable devices, where standby mode efficiency with 100-mA load. To enhance efficiency in light load conditions and to achieve a wide operation load range, loss minimization by balancing conduction and switching losses is adopted, and a dynamic power-gating scheme is applied for pulse frequency modulation mode operation. Moreover, robust dual-mode operation is implemented with a time-based control scheme, which enables operation with a lower peak current for optimal loss balancing. The proposed converter is fabricated in 130-nm complementary metal-oxide-semiconductor process with an area of 1.7 mm2. The measured efficiency for supplying 12-V output from 5.5-V input is 91% at its peak load of 40 mA and 85% with an extremely light load of 200 μA. It also achieves a wide dynamic load range from 200 μA to 600 mA for >85% efficiency and from 2 to 150 mA for >90% efficiency.

A D-Band Dual-Mode Dynamic Frequency Divider in 130-nm SiGe Technology

In this work, a dual-mode (divide-by-2 and divide-by-3) dynamic frequency divider is presented. A tunable delay gated ring oscillator (TDGRO) topology is proposed for dual-mode operation and bandwidth extension. It uses a 130-nm gate length SiGe BiCMOS technology with the $f_{t}$ and $f_{\mathrm {max}}$ of 250 and 370 GHz, respectively. Verification shows that it works at $W$ -band from 70 to 114 GHz (47.8% bandwidth) for divide-by-2 and works at $D$ -band from 105 to 160 GHz (41.5% bandwidth) for divide-by-3. This divider can be used in integrated phase-locked loops (PLLs) at millimeter-wave frequencies.