Solid-state Switches Research Articles

Performance analysis of Buck-Boost and Cuk converter-fed brushless DC motor drives

This paper presents a detailed analysis on the performances of Buck-boost and Cuk power factor converter-fed sensor-less Brushless DC (BLDC) motor drives. BLDC motors are widely preferred for low-power applications due to their high efficiency, faster dynamic response, high ruggedness, high power density, long operating life, noiseless operation, high torque-to-weight ratio and higher speed ranges. Speed of the drive is controlled by varying the DC-link voltage of the Voltage Source Inverter (VSI) feeding the motor. Switching losses in the Voltage Source Inverter are reduced by electronic commutation of the BLDC motor, thereby switching the solid state switches of the VSI at line frequency. The converters are operated in Discontinuous Conduction Mode (DCM) to achieve inherent power factor correction (PFC) at AC mains. Voltage mode control is used adjust the duty ratio of the PFC converter switch. Direct Back-EMF Zero Crossing Detection method is used for the sensor-less control of the BLDC motor. The performance of the drive is evaluated using the selected converters over a wide range of speeds. A unity power factor is achieved with power quality indices acceptable within the recommended limits of IEEE 519 standard.

Modelling and Simulation of Reduce Harmonic Distortion in Non-linear Loads

Harmonic distortion is a problem that can be caused by the use of power electronic devices. The effect of harmonics has an impact on changes in the input voltage source waveform which is referred to as wave defects. This incident has an impact on electronic faults and overheating of the power transformer coil as a supplier. One cause of the emergence of harmonics is the use of non-linear loads on the electric power system. Utilization of non-linear loads such as arc fires (metal casting), welding, magnetic core in transformers and rotating machines, synchronous machines, adjustable speed drives, solid-state switches High voltage DC transmission and Photovoltaic invertors can produce input wave defects. The filter is modelled through a reference current which is used as a PWM pulse generator reference signal to trigger the inverter, further generating a filter current that is injected into the system. Inverter control uses the Propositional Integrator (PI) control approach. From the simulation test results using the Psim software, it is shown that the recorded input waves due to harmonic distortion can be corrected by placing an active filter into the power system.

Portable Microwave Head Imaging System Using Software-Defined Radio and Switching Network

Head imaging plays an imperative role in the detection and localization of conditions affecting the brain, such as strokes, cancerous tumors, and hemorrhages caused by trauma. Current systems require the patient to be transported to the imaging device that increases the time taken to apply treatments, allowing the patient's condition to worsen. This paper proposes a portable microwave head imaging system that can easily be taken to the patient. The system utilizes a novel combination of a software-defined radio and solid-state switching network to collect the imaging data and operates in the frequency band of 0.85–2 GHz. It can capture input signals over a range of approximately 106 dB, which is suitable for detecting realistic brain injuries. The concept has been validated through experimental data collection and confocal image generation and was capable of producing images in less than 1 min. A simplified head phantom was developed for gathering the verification data and proved that the system was capable of locating targets with dielectric properties similar to brain tumors and bleeds. The presented design is highly accessible and achieved through being small, light, and inexpensive, which are key factors that could help save lives in time-critical medical emergencies.

Solvent vapour induced rare single-crystal-to-single-crystal transformation of stimuli-responsive fluorophore: Solid state fluorescence tuning, switching and role of molecular conformation and substituents

Supramolecular interactions and molecular conformations play significant role on producing fluorescent polymorphs with tunable emission in the solid state from single fluorophore. External stimuli-induced structural transformation from one polymorph to another polymorph without losing single crystalline character (single-crystal-to-single-crystal transition (SC-SC)) provides perfect model to understand the structure-property of molecules in the solid state and designing new functional fluorescent materials. Herein we have tailored the substituent groups in the aggregation-induced-emissive (AIE) tetraphenylethylene (TPE) based donor (D)-acceptor (A) fluorophores (TPPA-1-6) and explored fluorescent polymorphs formation and SC-SC transition in the solid state. TPPA-1 showed conformational fluorescent polymorphs via twisted and co-planar conformation between TPE phenyl group and cyanophenyl acceptor phenyl ring. However, single crystal analysis of other derivatives revealed that substituent groups and supramolecular interactions control the molecular conformation and SC-SC transition. Fluorophore with same substituent but positional change also show drastic effect on the fluorescent polymorphs formation and SC-SC transition. Substituents that can form strong intermolecular interactions stabilize the less stable co-planar structure whereas bulky substituents with weak intermolecular interactions produced twisted or both conformers. Photophysical, powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC) and thermogravimteric (TG) analysis were performed to substantiate and get insight on the structural transformation. The formation of fluorescent polymorphs and SC-SC transition exhibited tunable and switchable solid state fluorescence. The non-planar TPE core has been made use to demonstrate high contrast stimuli induced reversible fluorescence switching. Overall, the present studies attempted to gain information on the structural design for developing SC-SC transforming functional organic fluorescent materials that could be of potential interests for optoelectronic and display devices.

A Novel DC Chopper With MOV-Based Modular Solid-State Switch and Concentrated Dissipation Resistor for ±400 kV/1100 MW Offshore Wind VSC-HVDC System

A dc chopper (DCC) is one of the key equipment in voltage-sourced converter-based high-voltage dc transmission systems with offshore wind power access. Combining the complementary advantages of concentrated and modular DCCs, a novel DCC with modular solid-state switches and a concentrated resistor (MC-DCC) is proposed. The non-long-term work attribute of the DCC provides opportunities to apply metal oxide varistors in modularizing series solid-state switches, thereby removing the capacitors for voltage balance. A method of designing the MC-DCC is introduced on the basis of the analysis of system requirement. Finally, prototype experiments are conducted to verify the effectiveness of the MC-DCC.

Research on effect of circuit parameters on breaking characteristics of mechanical DC circuit breaker

Whether fault current can be broken quickly and reliably depends on dynamic characteristics of LC resonant commutation branch of mechanical DC circuit breaker.Thereby, the breaking characteristics of mechanical DC circuit breaker based on LC resonant commutation are studied in this paper. The topological structure and action time sequence of mechanical DC circuit breaker based on LC resonant commutation are introduced firstly. Transient voltage and transient current equations of mechanical DC circuit breaker based on LC resonant commutation are deduced on the basis. The influence of fast mechanical switch contact gap, resonant capacitor C, charging voltage of resonant capacitor C, resonant inductance L, solid-state switch turn-on time and other parameters on fault current, breaking time and other breaking characteristics are studied finally, thereby providing feasibility basis for parameter design of LC resonant commutation branch.

Voltage-gated optics and plasmonics enabled by solid-state proton pumping

Devices with locally-addressable and dynamically tunable optical properties underpin emerging technologies such as high-resolution reflective displays and dynamic holography. The optical properties of metals such as Y and Mg can be reversibly switched by hydrogen loading, and hydrogen-switched mirrors and plasmonic devices have been realized, but challenges remain to achieve electrical, localized and reversible control. Here we report a nanoscale solid-state proton switch that allows for electrical control of optical properties through electrochemical hydrogen gating. We demonstrate the generality and versatility of this approach by realizing tunability of a range of device characteristics including transmittance, interference color, and plasmonic resonance. We further discover and exploit a giant modulation of the effective refractive index of the gate dielectric. The simple gate structure permits device thickness down to ~20 nanometers, which can enable device scaling into the deep subwavelength regime, and has potential applications in addressable plasmonic devices and reconfigurable metamaterials.

Improving Low-Voltage DC Circuit Breaker Performance Through an Alternate Commutating Circuit

Current interruption in dc circuits is more challenging than in their ac counterparts due to the absence of natural current zero-crossing and resistive nature of the dc grids. This article summarizes the current dc breaker technologies and proposes new alternate methods for low-voltage applications. The proposed mechanisms utilize two switches, of which one generates zero crossing with an alternate oscillatory circuit for the other one, which can be a conventional ac breaker and is used in the main circuit. This is different than the conventional single-switch commute-and-absorb method used in high-voltage dc systems. It is shown that the proposed oscillatory circuit improves the fault current extinction and significantly reduces the voltage slew rate of conventional mechanical and solid-state switches. Thus, the proposed mechanism is capable of interrupting high dc currents with a minimal arc through a less expensive ac circuit breaker. Simulation and hardware results are provided to show the efficiency of the proposed breakers.

Power Management with Dynamic Power Adaption for a Rotational Energy Harvester in a Maritime Gearbox

Rotational Energy Harvesting becomes increasingly important for rotating sensor applications. Most of these applications rotate with changing revolution speed, which is a significant challenge for the energy harvesting system. This work presents an energy harvesting system for rotational motion with a new power management concept to generate energy for a wireless condition monitoring system. The challenge is to generate enough energy with a high efficiency factor at the minimum revolution speed but also to avoid problems with energy excess and high voltages at the maximum revolution speed. The power management includes solid state relays for coil switching to avoid the generation of excess energy that would lead to increased temperature. At 500 rpm the energy harvester generates 193 mW. With an efficiency of 54% the power management provides an output power of 106 mW.

Protecting A Low Voltage Direct Current System Using Solid-State Switching Devices for DC Grid Applications

LVDC transmission has fewer distributional losses than AC distribution, integrating renewable sources, greatly increasing the mix of clean energy sources in the standard grid in the next decade and this has become a trend that is likely to continue. As an additional benefit, DC electrical power is oftentimes seen as beneficial to applications that use cleanly generated, renewable power. Considering DC power system design, and focusing on fault protection and the systems DC circuit breaker, are system priorities. Only solid-state circuit breakers (SSCB) should be considered to obtain advanced system topography. A new type of solid state circuit breaker is being developed as a new power device for LVDC power networks to replace the EMCB. The only suitable candidate for this task is the insulated gate bipolar transistor (IGBT). Development of DC grid protection allows for the development and improvement of new power electronic devices, focusing in on the application for medium to low voltage DC grids, a rapidly acting switching function as well as fault current limiting features. To avoid nuisance tripping, fault current limiting function can be satisfactorily accomplished by extending the elapsed time using the same control circuit. This paper introduces a novel circuit breaker model for LVDC, which utilizes a coupled inductor circuit breaker, and a mathematical model of IGBT has been developed.

Blue-/NIR Light-Excited Fluorescence Switch Based on a Carbazole-Dithienylethene-BF2bdk Triad.

The development of novel solid-state fluorescence switches, particularly triggered by visible light, is of increasing interest for the potential application in optical data storage and super-resolution fluorescence microscopies. In this study, two carbazole-dithienylethene-BF2bdk triads CDB1 and CDB2, suspending carbazole and BF2bdk moieties on both sides of dithienylethene unit, have been developed. They exhibit blue-/NIR light-controlled photochromism with solvent-dependent characteristics. Moreover, CDB1 (o) reveals blue-/NIR light-induced reversible fluorescent switching behaviors in toluene, chloroform, poly(methyl methacrylate) (PMMA) film, and powder state, while its analogue CDB2 (o) in the powder state exhibits no fluorescence due to a strong intermolecular π-π stacking interaction, and the fluorescent switching performance is observed only in toluene and PMMA film. The density functional theory calculations further validate the differences in their optical properties in the solution and powder states.

Simple and Compact Longitudinally Excited CO2 Laser Driven with A Fast High-Voltage Solid-State Switch

Simple and Compact Longitudinally Excited CO2 Laser Driven with A Fast High-Voltage Solid-State Switch

2D materials for quantum information science

The transformation of digital computers from bulky machines to portable systems has been enabled by new materials and advanced processing technologies that allow ultrahigh integration of solid-state electronic switching devices. As this conventional scaling pathway has approached atomic-scale dimensions, the constituent nanomaterials (such as SiO2 gate dielectrics, poly-Si floating gates and Co–Cr–Pt ferromagnetic alloys) increasingly possess properties that are dominated by quantum physics. In parallel, quantum information science has emerged as an alternative to conventional transistor technology, promising new paradigms in computation, communication and sensing. The convergence between quantum materials properties and prototype quantum devices is especially apparent in the field of 2D materials, which offer a broad range of materials properties, high flexibility in fabrication pathways and the ability to form artificial states of quantum matter. In this Review, we discuss the quantum properties and potential of 2D materials as solid-state platforms for quantum-dot qubits, single-photon emitters, superconducting qubits and topological quantum computing elements. By focusing on the interplay between quantum physics and materials science, we identify key opportunities and challenges for the use of 2D materials in the field of quantum information science. 2D materials exhibit diverse properties and can be integrated in heterostructures: this makes them ideal platforms for quantum information science. This Review surveys recent progress and identifies future opportunities for 2D materials as quantum-dot qubits, single-photon emitters, superconducting qubits and topological quantum computing elements.

Effect of Structure on the Spin Switching and Magnetic Bistability of Solid-State Aryl Dicyanomethyl Monoradicals and Diradicals.

Stable organic radicals with switchable spin states have applications in medicine, biology, and material science. An emerging class of such spin-switchable radicals is based on dicyanomethyl radicals, which are typically thermally and air-stable species that form weakly bonded (closed-shell singlet) dimers at a lower temperature that rupture into electron paramagnetic resonance-active diradicals at a higher temperature. However, thus far, the study of these dicyanomethyl radicals has focused on their solution-phase behavior. An understanding of how chemical structure affects the solid-state spin switching behavior for these radicals is unknown. Here, we examine the solid-state spin crossover behavior of 6 monoradicals and 10 tethered diradicals and demonstrate that these species also undergo spin switching in the solid state. We find that the susceptibility for solid-state spin switching for the intermolecular dimers is weakly correlated to the solution-phase Gibbs free energies of dimerization, but no apparent correlations are seen between the solution-state free energies for the intramolecular dimerization and the solid-state behavior. Furthermore, intramolecular diradical dimers have greatly enhanced temperature-responsive behavior compared to their intermolecular counterparts. Crystalline and amorphous powders of the same radicals feature similar spin switching behavior, but the crystalline materials have slower bond-rupture kinetics at higher temperatures, suggesting that solid-state packing effects are an important kinetic consideration. An interesting feature of these systems is that, upon cooling down to room temperature after heating, some radicals remain trapped in the solids, indicating magnetic bistability, while others partially or fully return to the diamagnetic dimers. This work provides insights into how chemical structure affects spin crossover in the solid state for this new class of air-stable radicals, the knowledge of importance for the construction of dynamically responsive solid-state materials, and organic spin crossover polymers.

Implementation of IoT With Image Processing in Greenhouse Monitoring System

Greenhouse automation system using Internet of Things (IoT) is a technical approach that benefits farmers by the automation and control of the greenhouse environment including plants health monitoring. Farmers' activities in the greenhouse are considered important in terms of producing strategic food for the population. In general, greenhouses are usually affected by the weather and plant diseases, as a result, their yield can be minimized and thus income is reduced. Through the analysis of the current situation of small-scale greenhouses, this paper proposes a low-cost solution for controlling, identifying, and classifying of infected plant leaves and automation of agricultural greenhouse. Design and prototype development of the proposed project has been done using Raspberry Pi, NODE MCU SP8266, different sensors and MATLAB. The programming language, MATLAB, is used to classify infected plant leaves, and sensors have been used to measure temperature and humidity of the greenhouse environment. In addition, controlling of actuators have been attained through solid state relays in order to turn the water drip system on or off upon reaching the predetermined threshold value. Finally, the greenhouse farmers interact with the proposed system via the cloud-based platform. This greenhouse automation system will benefit greenhouse farmers by enabling them to automatically monitor and control the greenhouse environment without their direct supervision.

A Novel Mixture Solid-State Switch Based on IGCT With High Capacity and IGBT With High Turn-off Ability for Hybrid DC Breakers

Hybrid dc circuit breakers (HCBs) usually require a large number of insulated-gate bipolar transistors (IGBTs) with high turn- off capability for series and parallel connections. This requirement entails excessive cost. Compared with IGBTs, integrated gate-commutated thyristors (IGCTs) are another kind of fully controlled power device with high surge current and voltage capability but are low cost. However, the weak turn- off capability of IGCTs hinders their application to high-powered HCBs. On the basis of the complementary advantages of IGBTs and IGCTs, this paper proposes a mixture solid-state switch (MSS) for HCBs that uses the switching action of several IGBTs to create a low-current condition that favors the turning off of large-scale series-connected IGCTs. The MSS topology can significantly reduce cost while maintaining the excellent performance of traditional solid-state switches. This study also introduces two different turn- off modes for MSS, namely, single oscillation and multiple oscillations. Finally, 25 kV/20 kA prototypes in both modes are developed to verify the effectiveness of the MSS topology.

Optimal Design of Diode-Bridge Bidirectional Solid-State Switch Using Standard Recovery Diodes for 500-kV High-Voltage DC Breaker

At present, it is usually necessary to use fast recovery type diodes to cooperate with the fast switching actions of fully controlled devices such as insulated-gate bipolar transistors (IGBTs). However, the specific nature of the working conditions of the diode-bridge bidirectional solid-state switch (DBSS) provides an opportunity to apply standard recovery diodes for this purpose, which helps to reduce the cost of the bidirectional switch. This letter presents the self-oscillation phenomenon that is caused by the recovery processes of the diodes in a DBSS. Then, the recovery effects of these diodes in different topologies are analyzed from the perspective of the DBSS and optimized designs for both the snubber circuit and the energy-absorbing circuit are proposed. A 500-kV dc breaker is realized based on the proposed DBBS using the standard recovery diodes, which can work reliably with IGBTs, and the cost of the resulting dc circuit breakers is greatly reduced.

Designing and implementation of energy‐efficient wireless photovoltaic monitoring system

AbstractPhotovoltaic (PV) cell usually shows unpredictable results due to abrupt change in environment. Environmental parameters such as temperature, dust factor, irradiance, and air mass have direct influence on the output of PV cells. Monitoring PV and its related environmental parameters is very important for understanding and analysis of PV in practical conditions. The PV parameters have been found useful in many ways like reliability analysis, life cycle costing, returns on investment calculation, loss of load probability, and optimal designing of PV power supplies. Currently, designed PV monitoring systems (PVMS) are reported to be expensive, complex, and are limited in their applications, out of which only few are wireless. In this article, we design and implement a simple cost‐effective and wireless PV monitoring solution. The design PVMS is based on microcontrollers, light‐dependent resistors, current sensor, analog‐to‐digital converter, solid state relays, ZigBee (XBee) wireless microcontroller, and LabVIEW‐based data logging software. The designed PVMS performs the real‐time analysis and data logging of open circuit voltage (Voc), short circuit current (Jsc), ambient temperature (Ta), cell temperature (Tcell), and maximum power point. In addition, real‐time I‐V and P‐V characterization of PV module is another valuable feature embedded in the designed PVMS.

Noise Synthesis Technique in Time Domain for Metrology Application

We developed a prototype radiometer system to implement a time-domain noise synthesis technique. A solid-state (SS) switch synthesizes noise signals from the outputs of two synchronized electromechanical (EM) switches. The input ports of EM switches are terminated by one unknown noise source, one known cold noise reference, and two known ambient noise references. The magnitude of the synthesized noise signals can be varied by the duty cycle of the transistor–transistor logic (TTL) pulse that controls the SS switch. By regulating the TTL pulse, a null balance is reached when the power level of the synthesized noise signals equal to that of the ambient noise reference. The noise synthesis radiometer represents a major step forward over the conventional noise-injection radiometer, enabling highly efficient measurements of the noise temperature with improved precision. The uncertainty due to nonidentical input-impedance states is also properly accounted for. Several future works are suggested to further improve the system performance.

Experimental study of pumps in a pipe bench

This paper presents an experimental study of radial flow propeller pumps in a pipe bench. For the development of the research, flow and pressure sensors are used in order to determine the fluctuations and the characteristics dynamics fluid of the pump. A control system was used using a Solid-State Relay to vary the speed of the pump and a virtual platform coupled to a data acquisition system to characterize the network. The characteristic curve of the propeller pump was obtained with a value of R2=0.97, in addition the characteristic curves of the hydraulic network for turbulent flow are calculated with the Reynolds number between 13821 and 81521. Finally, the volumetric losses are calculated in the pipe, which equals 10% for a flow of 10 l/min and as the flow increases up to 6 times the value decreases to 2%.