Independent Power Supply Research Articles

Fully printed origami thermoelectric generators for energy-harvesting

Energy-harvesting from low-temperature environmental heat via thermoelectric generators (TEG) is a versatile and maintenance-free solution for large-scale waste heat recovery and supplying renewable energy to a growing number of devices in the Internet of Things (IoT) that require an independent wireless power supply. A prerequisite for market competitiveness, however, is the cost-effective and scalable manufacturing of these TEGs. Our approach is to print the devices using printable thermoelectric polymers and composite materials. We present a mass-producible potentially low-cost fully screen printed flexible origami TEG. Through a unique two-step folding technique, we produce a mechanically stable 3D cuboidal device from a 2D layout printed on a thin flexible substrate using thermoelectric inks based on PEDOT nanowires and a TiS2:Hexylamine-complex material. We realize a device architecture with a high thermocouple density of 190 per cm² by using the thin substrate as electrical insulation between the thermoelectric elements resulting in a high-power output of 47.8 µWcm−² from a 30 K temperature difference. The device properties are adjustable via the print layout, specifically, the thermal impedance of the TEGs can be tuned over several orders of magnitudes allowing thermal impedance matching to any given heat source. We demonstrate a wireless energy-harvesting application by powering an autonomous weather sensor comprising a Bluetooth module and a power management system.

Design and Development of Real-time landslide early warning system through low cost soil and rainfall sensors

Development of cost effective early warning systems is of paramount importance for real time monitoring of natural hazards such as Landslides, Floods, Earthquake etc. The present research work discusses about the design and development of cost effective early warning system for monitoring shallow debri landslides. The warning system consist of field unit and remote network interface. The field system includes the rainfall, temperature, humidity, soil temperature, soil moisture and Tiltmeter as primary sensors for monitoring the landslide movements with an independent power supply of 50 W solar panel. The datasets that are received are stored in the local data logger with the help of microsd card. Real time monitoring of the datasets and analysis was made possible by storing the datasets in remote Database Management System. These datasets are transmitted via the Global System for Mobile communication module installed at the field unit. In order to convey the alerts during emergency time a simple visual message has been adopted for the current model. Level I, Level II and Level III, Level I being the threshold values are within the desired limit and actions are not necessary and Level III denotes threshold values have exceeded the set limit and warning are issued to local stake holders. A pilot study of the Early Warning System has been installed on site for quality checks of the sensor & data and the results were monitored. The model developed not only can address the early warning signs of mass movement but also can be calibrated to predict flood in major streams based on rainfall intensity.

Mobile installations for electro treatment of soils and plants with the use of photovoltaic systems as power supply

The technology of electro processing by UV- radiation for cultivation of cotton is considered. By results of experimental researches optimum parameters for treatment soils with ultraviolet radiation lamps for increasing the accumulation of the most mobile nitrate forms of nitrogen are defined. Prospects of transition of UV-lamps to light-emitting diodes (LED) as way of improving efficiency of processing, and creation of independent power supply by means of photo-electric batteries are shown.

Method for designing drop-of-wire recognition systems on sections of undistorted two-wire power transmission lines

In this work a general statement of the problem of designing distributive electrical systems that recognize breakage of wires on sections of power lines using a multifunctional wire with an isolated residential wire is formulated. The use of overhead wires with the proposed construction of the housing will make it possible to solve many electrical problems very easily and cheaply without the use of expensive equipment. The correspondence table of the information current values of the power supply unit I 0 and of the wire breakdowns on the sections in the two-wire transmission line is obtained by simulation. The proposed method of diagnostics and monitoring of the state of power lines is not expensive and allows the maintenance staff, being at the substation, to detect rapidly and remotely the breakage of wires on the parts of the network and the distance to it, In order to ensure that the repair crew is sent to the exact location of the damage, this will improve the reliability of the electrical supply to consumers. This is achieved by the fact that the information wire has an independent power supply and thus allows for control of the network at any time.

Experimental Study of the Cathode Modulation for the TH2103A Klystrons on HL-2A Tokamak

The 3.7 GHz high power klystrons TH2103A are widely used in the lower hybrid current drive system for the tokamak experiment. In order to avoid the tetrode and simplify the power supply system, the cathode modulation for high power TH2103A klystron is experimentally studied. Both the independent Anode Power-Supply (APS) and a Passive Potential Divider (PPD) configuration are investigated. The beam current goes to zero in 10 ms in the APS mode directly. As a result, a stable beam current is achieved in the PPD mode when the resistor from the anode to the ground is less than 30 k Ω, the cathode voltage is below − 45 kV and its rise-time is between 100 and 150 μs. The threshold of the resistor and the rise-time may be caused by the inductance of the wire-wound resistors. Although the anode current exceeds 10 mA when the cathode voltage rises and falls, 5 years operation validates the safety of the klystron. A practical and simple method is developed to operate the anode modulation klystron by cathode modulation on HL-2A, without using a dedicated tetrode.

Study of piezoelectric behaviour of sputtered KNbO3 nanocoatings for flexible energy harvesting

Novel potassium niobate (KNbO3) nanocoatings were sputtered on polyethylene naphthalate (PEN) substrates at different sputtering voltages and concentrations of sputtering gas. The relations growth time - thickness and sputtering voltage-deposition speed were established and the vacuum deposition modes were optimized. This was realized, in order to correlate the microstructure, surface morphology and the growing conditions for the nanosized KNbO3 films. Uniform coatings with variety of thicknesses were obtained without overheating degradation of the substrates at process parameters Us and PAr varying from 0.6 kV to 0.9 kV and from 1 × 10−2 Torr to 9 × 10−3 Torr, respectively. New Al/KNbO3/Al energy harvesting element was fabricated and tested on tension-compression cycles. For the samples, showing the lowest surface roughness of the KNbO3 film (3.6%), maximum piezoelectric voltage of 431 mV was measured at loading up to 3 kg. Basic electric parameters, such as capacitance, contact and bulk resistance of the piezoelectric element, involving KNbO3 film, produced at the optimum sputtering conditions, were measured as a function of the applied mass load. Output electrical power of 2.324 μW was obtained at maximum mechanical loading, which is comparable with the results for lead-containing thin film harvesters. Theoretical analysis of the novel elements was made based on their dielectric behaviour in terms of polarization type. They were connected to passive power management system for operation as an independent power supply for low-power electronics.

A Differential Electric Drive for Electric Vehicles with an Independent Power Supply

In this paper, we consider the effectiveness of using a twin-engine electric drive from the point of view of acceleration dynamics and energy efficiency. To take into account the acceleration time of the electric vehicle and the energy consumed during the transition process, evaluation criterion G was introduced. By a “twin-engine system” is meant a system of electric drive of a wheel pair through two independent mechanical channels: the first is a “high-torque” channel implemented through the use of a gearbox with a high gear ratio, and the second is a “high-speed” channel implemented through the use of a gearbox with a low gear ratio or without a gearbox at all. The summation of power is carried out by means of a differential gear. We performed mathematical modeling of the operation of such a system. Asynchronous electric drives with vector control, which operate in the torque source mode, are used as electromechanical converters. An algorithm and a system for distributing torque between two channels are developed. The gear ratio of the “high-torque” channel gearbox was optimized by the criterion of G minimum. A quantitative comparison and analysis of transient acceleration processes in single- and twin-engine systems were performed based on the example of a 30-kW electric race car. It is concluded that it is effective to use a twin engine system for specific types of electric vehicles.

An Efficient Ultra‐Flexible Photo‐Charging System Integrating Organic Photovoltaics and Supercapacitors

AbstractFlexible and biocompatible integrated photo‐charging devices consisting of photovoltaic cells and energy storage units can provide an independent power supply for next‐generation wearable electronics or biomedical devices. However, current flexible integrated devices exhibit low total energy conversion and storage efficiency and large device thickness, hindering their applicability towards efficient and stable self‐powered systems. Here, a highly efficient and ultra‐thin photo‐charging device with a total efficiency approaching 6% and a thickness below 50 µm is reported, prepared by integrating 3‐µm‐thick organic photovoltaics on 40 µm‐thick carbon nanotube/polymer‐based supercapacitors. This flexible photo‐charging capacitor delivers much higher performance compared with previous reports by tuning the electrochemical properties of the composite electrodes, which reduce the device thickness to 1/8 while improving the total efficiency by 15%. The devices also exhibit a superior operational stability (over 96% efficiency retention after 100 charge/discharge cycles for one week) and mechanical robustness (94.66% efficiency retention after 5000 times bending at a radius of around 2 mm), providing a high‐power and long‐term operational energy source for flexible and wearable electronics.

Gearbox Development for an Emergency Brake System of the Wind Turbine

The article justifies the need to use independent power supply sources in the Arctic regions. It gives arguments in favour of using wind-driven power plants as autonomous power sources. It describes the problems of operating wind energy equipment in the arctic climate. As a solution of the above operational problems, it is proposed to use an emergency brake system in wind power plants. We proposed a design of an emergency brake system exemplified by a 3 kW vertical-axial wind turbine. We calculated the gearbox parameters for the proposed design and created a computer model of the gearbox based on the obtained parameters. We also analysed the advantages of the developed gearbox and the design of the emergency brake system in general.

A Microgrid Concept for Thermal and Electrical Energy Supply of a Sport Recreation Center: Case Study S.R.C.A

A microgrid concept for the thermal and electrical energy supply of a Sport-Recreation Center Ajdinovići (S.R.C.A.) has been proposed in this paper. A self-contained and intelligent power distribution grid has been developed for this case, taking into account the location, locally available renewable energy sources and the very purpose of this center. Comparative analyses between independent power supply through the proposed hybrid power system and the supply over the transmission and distribution network were performed. Technical and economical optimization of an energy system with distributed power generation was done by applying HOMER and DIgSILENT PowerFactory professional software tools. As a result, hybrid power system is more cost-effective than the conventional supply by the power distribution network, microgrid meets the technical criteria based on the analysis of power flows and the stability of the network has been achieved. Establishment of energy independence for the existing S.R.C.A. besides economic factor will show several benefits regarding better use of locally available resources, reduction of CO2 emissions and energy efficiency increment as well as an employment opportunity to the local people, thus contributing to the sustainability of the region.

Energy harvesting thermocell with use of phase transition

A thermocell that consists of cathode and anode materials with different temperature coefficients (α = dV/dT) of the redox potential (V) can convert environmental thermal energy to electric energy via the so-called thermal charging effect. The output voltage Vcell of the current thermocell, however, is still low (several tens mV) and depends on temperature, which are serious drawbacks for practical use of the device as an independent power supply. Here, we report that usage of phase transition material as electrode qualitatively improve the device performance. We set the critical temperature (Tc) for the phase transition in cobalt Prussian blue analogue (Co-PBA; NaxCo[Fe(CN)6]y) to just above room temperature, by finely adjusting the Fe concentration (y = 0.82). With increase in the cell temperature (Tcell), Vcell of the NaxCo[Fe(CN)6]0.82 (NCF82)/NaxCo[Fe(CN)6]0.9 (NCF90) cell steeply increases from 0 mV to ~120 mV around 320 K. Our observation indicates that the thermocell with use of phase transition is a promising energy harvesting device.

Analysis of a Fault-Tolerant Module-Combined Stator Permanent Magnet Synchronous Machine

To solve the problems of large-size machining and complex control of fault-tolerant permanent magnet machines, a module-combined stator permanent magnet synchronous machine is proposed in this paper. The winding of the module-combined stator has two forms: large and small spans. The independent power supply of each module is adopted to decouple the electricity between each module, which enhances the manufacturing flexibility and the fault-tolerant ability of the motor. A mathematical model of the module-combined stator permanent magnet synchronous machine is established, and the design method of the machine is summarized. Then the analytical formula of the radial force acting on the stator under asymmetric operation is deduced. In addition, the torque-angle characteristics of the machine and the factors affecting the radial force are studied. Finally, the machine is prototyped, and both simulation and experiment are used verify the rationality of the proposed design.

Research on fuel cell energy storage control and power generation system

In order to realize the continuous stability of photovoltaic power generation system and the controllability of thermal energy storage, a photovoltaic fuel cell combined power generation system consisting of photovoltaic cell array, proton exchange membrane fuel cell, alkaline electrolysis cell and super capacitor is proposed. The system, at the same time, establishes the mathematical model of its various components and the system cost model, designs the thermal energy distribution of the thermal energy storage management coordination system, and uses the high efficiency battery to meet the load requirements of the power system. In addition, the paper uses simulation technology as a research method to build a simulation model of hybrid fuel cell thermal energy storage control and power generation system, and analyzes the system?s thermal energy supply and demand balance. The simulation results confirm that the photovoltaic fuel cell hybrid power generation system has high economic performance, can meet the user?s power and thermal energy requirements, and realizes the requirement of completely independent power supply.

Preliminary Evaluation of the HOBO Data Logging Rain Gauge at the Chuzhou Hydrological Experiment Station, China

As a tipping bucket rain gauge, the HOBO Data Logging Rain Gauge RG3-M (RG3-M) has been widely used for the field precipitation observation owing to its superiority of independent power supply by a small portable battery. To quantify the measurement accuracy of the RG3-M gauge, a standard Manual Gauge (MG) and eight other models of tipping bucket rain gauges were installed at the Chuzhou hydrological experiment station of China. In this study, we first compared and investigated the accumulated mounts of 18 rainfall events of two RG3-M gauges benchmarked by the standard MG. Then, five typical rainfall events were chosen to further analyse the observed accuracy of the RG3-M gauge for different rainfall intensities at hourly temporal scale. Finally, the impacts of wind speed and rainfall intensity on the precipitation measurements of the RG3-M gauge were preliminarily explored. Results indicate that the RG3-M gauge measurement generally underestimates rainfall approximately −4% against the standard MG observation, but the maximum deviation even reaches −12.87%. In terms of the hourly rainfall process, the reliable measurement scope of the RG3-M gauge is ranging from 1.5 to 3 mm/h; however, it should be noted that the underestimation is rather significant at the higher rainfall rates (>6 mm/h). Last, it was found that rainfall intensity is a nonnegligible factor for influencing the measurement of the RG3-M gauge. But the windy effect seems to be insignificant in our experiments, which might be attributed to the similar exposure of the compared gauges.

Two Correlated Interferometric Optical Fiber Systems Applied to the Mining Activity Recordings

In order to meet new directions of research in the field of rotational seismology, a registration of rotation phenomena from mining seismic shocks was carried out by two interferometric optical systems. Applied instruments are based on the Sagnac effect and measure the rotation rate in a direct way. Systems have a wide measuring range both in the case of signal amplitude as well as frequency range. Allan variance analysis has indicated that they have proper parameters for the rotational seismology investigation (angle random walk equals 3.20 · 10−8 rad/√s, as well as bias instability equals 2.41 · 10−8 rad/s). Moreover, regarding applied special electronic processing, they provide rotation rate as an output instead of a change of an angle like in commercially available fiber optic gyroscopes. The optical head of the constructed systems uses depolarized light in order to avoid polarization effect. Systems are remotely controlled by the Internet and adapted to an independent power supply which makes them fully autonomous. Correlation between data gathered by two systems applied in a geophysical observatory in Ksiąz, Poland, have been calculated according to the person's correlation coefficient.

Assessment of a stand‐alone hybrid solar and wind energy‐based electric vehicle charging station with battery, hydrogen, and ammonia energy storages

AbstractSince the main objective of expanding the deployment of electric vehicle (EV) usage is to reduce the dependency on carbon‐based fuels, it is essential to consider eco‐friendly and renewable sources to generate the power needed for charging those vehicles. This study suggests and analyzes a stand‐alone solar and wind energy‐driven integrated system with electro/chemical energy storage to provide independent and uninterruptable power supply for EV charging stations. Due to the intermittent nature of the utilized renewable energy sources, energy storage is a key concern to be considered in this study. Therefore, in addition to batteries, hydrogen and ammonia are considered as energy storage media, which can be converted into electricity through fuel cells on demand. The results show that with selected commercialized photovoltaic power plant covering an area of about 1500 m2, a 250 kW rated wind turbine, 650 kWh Li‐ion storage batteries, 30 m3 storage of H2 in gas form, and 5 m3 storage of NH3 in liquid form, a grid‐independent charging station sufficient for fast charging of 50 number of EVs per day can be achieved. Additional suggestions are proposed to better manage the energy storage within the charging stations based on short‐term and long‐term operations.

Dynamic Capabilities of an Energy Storage-Embedded DFIG System

Power electronic-based wind turbine generators (WTGs) are capable of providing inertial response to the grid by releasing kinetic energy from the turbine blade; thus, as conventional power plants are retired, the reduction of online inertia can be compensated by designing frequency controls for the WTGs. Deployment of energy storage technology for renewable generations has been increased to have the renewables centralized with a system operator as an independent power supply by making up for their nature of generation. In addition, the cost of energy storage has dropped over time and global research activities on energy storage have been funded by private industries and governments. This paper investigates the opportunity of deploying an energy storage on a doubly fed induction generator (DFIG)-based WTG to respond to the system frequency, and then explores dynamic capabilities of the energy storage-embedded DFIG to boost its contribution while the frequency response is being provided by the power system's online inertia; thus, enabling an effective delivery of ancillary services to the system. To do this, the dynamic models of DFIG and energy storage are combined and simulated under the different operating conditions of a DFIG, such as subsynchronous, synchronous, and supersynchronous operations, using the PSCAD.

Impact of Total Ionizing Dose on Low Energy Proton Single Event Upsets in Nanometer SRAM

The impact of the total ionizing dose (TID) on a low energy proton single event upset (SEU) in a 65-nm static random access memory (SRAM) is investigated based on a low energy proton accelerator. The body potential of the P-well is elevated due to charge depletion along the sidewall of shallow trench isolation (STI) induced by TID irradiation. The radiation-induced narrow channel effect causes a decrease in the area and the thickness of the SEU sensitive volume (SV), further resulting in the low energy proton SEU cross section being lowered in 65-nm SRAM with an external independent power supply of the memory array. The impact of the TID on the low energy proton SEU cross section is dependent on test patterns written to the memory array during TID irradiation and SEU testing. The low energy proton SEU cross section is the highest when the complement test pattern is written to the SRAM memory array during TID irradiation and SEU testing compared with the same and half complement patterns.

Research Status and Prospects of Monitoring Sensor Energy Supply Technology

The self-powered technology of the power system measuring device is a power-taking method from the power source to the load according to the principle of electromagnetic induction or energy exchange. Compared with the traditional wired method, it does not need independent power supply to power the device, and has the advantages of high intelligence and high reliability, especially in some special occasions, and will be more widely used. It mainly expounds the existing four mainstream self-powered implementation methods, and analyzes its working principle, transmission efficiency and existing problems. According to the research status of various power supply methods, the future development trend of self-powered technology is prospected.

A design of ± 0.28 ppm temperature-compensated crystal oscillator in a 0.35 μm CMOS process

A high-performance temperature-compensated crystal oscillator (TCXO) is presented. This paper proposes a new temperature sensor with a Σ–Δ analog to digital converter, and a voltage-controlled crystal oscillator, respectively, using two sets of independent power supply. The presented TCXO is implemented in a 0.35 μm 2P3 M standard complementary metal-oxide semiconductor process at a power supply of 3.3 V, and the total power dissipation is 21 mW. Measurement results indicate that the designed TCXO achieves ± 16 ppm output frequency tuning range and 135, − 141 dBc/Hz phase noise at 1, 10 kHz frequency offset, respectively, by using a 40 MHz fundamental AT-cut crystal resonator. With the temperature compensation, the frequency deviation is within ± 0.28 ppm over − 40 °C to 85 °C.