Dedicated Power Source Research Articles

Magnetic field generator for the calibration of magnetometers and electromagnetic compatibility (EMC) and electromagnetic interference (EMI) compliance

A standard magnetic field generation system from 1 to 30 μT between DC and 20 kHz has been demonstrated for the calibration of DC/AC magnetometers. The system includes a laboratory-designed Helmholtz coil, shunt resistor, digital multimeter, and dedicated power source. The DC coil constant of the Helmholtz coil was determined to be 10.586 μT/A using a single-axis fluxgate magnetometer. The homogeneity analysis was carried out for the Helmholtz coil to identify the uniformity along the x, y, and z axes. The system for DC generation was standardized and compared by measuring the field values using a single-axis fluxgate magnetometer. Further, the system was validated for AC generation by a search coil with a known turn area (1.3767 ± 0.0027 m2). Moreover, the measured magnetic field values using a search coil were compared with a commercial magnetometer to identify the variation in generated and measured magnetic fields. The described system can have significant utilities in calibration, electromagnetic interference electromagnetic interference/electromagnetic compatibility (EMI/EMC) testing, magnetic susceptibility testing, and magnetic field therapy applications. The expanded uncertainty of the Helmholtz coil in generating a magnetic field was 0.2–1.6% (at k = 2) from DC to 20 kHz.

Ultracapacitor as selectable energy buffer in electric vehicle application

A method of ultracapacitor integration with a regenerative braking system for use in electric drive trains is presented in this paper. An ultracapacitor (UC) is an intermediary to store and provide energy on the DC bus in certain scenarios, such as during acceleration and regenerative braking. UC is used to avoid direct inrush loading on the battery, which the electric drive system may cause. The energy from UC is injected into the DC bus in compliment to the battery, for which a dedicated power source switch called the “Main Charge Controller” (MCC) is responsible. The charge discharge of UC is done through a bidirectional buck-boost converter (BDBBC). The use of UC to offload high energy demand from the battery and store energy recovered during regenerative braking helps improve the vehicle's life and per-charge range. The stored energy in UC can be obtained from the battery at the start. UC can also be charged at the time of charging. The design and the presented control are ideal for lightweight electric vehicles. The system uses a 39.9 kJ ultracapacitor, formed from market-available 50F 2.7 V units in a 52S configuration, storage, and a 6kWh battery. The simulated vehicle in battery only case provides a minimum of 154 km range in rough conditions, in best case scenario it provides a 200 km range. The proposed design provides an increased extended range compared to simple battery-based regenerative braking, in the case of this work the hybrid solution provides an addition of more than 30 km of additional range compared to a battery-only solution which is simulated for all the same conditions except without the addition of the UC and its control and handling system, resulting in a total range of 230 km. The speed control response achieved by the user is also very fast. Electric Vehicles have range limitations due to storage technology which is a high entry barrier for consumers looking for reliable vehicles without range anxiety, as storage technology progresses adoption will become easier. This work is an attempt at using hybrid storage and selective use of it, for improved range and sharper speed response. However, this work does not explore the aging of the storage components due to increased operational load and thermal stresses or application to alternate battery chemistries. This work is primarily focused on the vehicles that use lithium-based batteries.

SecrecyPerformance Analysis of Backscatter Communications with Side Information.

Backscatter communication (BC) systems are a promising technology for internet of things (IoT) applications that allow devices to transmit information by modulating ambient radio signals without the need for a dedicated power source. However, the security of BC systems is a critical concern due to the vulnerability of the wireless channel. This paper investigates the impact of side information (SI) on the secrecy performance of BC systems. SI mainly refers to the additional knowledge that is available to the communicating parties beyond transmitted data, which can be used to enhance reliability, efficiency, security, and quality of service in various communication systems. In particular, in this paper, by considering a non-causally known SI at the transmitter, we derive compact analytical expressions of average secrecy capacity (ASC) and secrecy outage probability (SOP) for the proposed system model to analyze how SI affects the secrecy performance of BC systems. Moreover, a Monte Carlo simulation validates the accuracy of our analytical results and reveals that considering such knowledge at the transmitter has constructive effects on the system performance and ensures reliable communication with higher rates than the conventional BC systems without SI, namely, lower SOP and higher ASC are achievable.

A Compact Duplexing Rectenna With Wireless Power Transfer and Harmonic Feedback Capabilities

A compact duplexing rectenna with wireless power transfer (WPT) and harmonic feedback capabilities is proposed in this work. It can not only convert the radio frequency (RF) power to the direct current (DC) power at the fundamental frequency, but also feedback the second harmonic signal from power limited receiver side (Rx) to transmitter side (Tx), for the purpose of stabilizing the DC outputs when the dedicated power source is moving. To this end, the duplexing antenna working at 0.915 GHz and 1.83 GHz with good isolation is designed at first. Then, a rectifier with second harmonic signal output is integrated on the ground of the duplexing antenna for a compact size. The rectifier exhibits a measured maximum power conversion efficiency (PCE) of 58% (at 5 dBm input power) and peak second harmonic signal power of -11 dBm with economic Schottky diodes SMS7630-005LF. Finally, the WPT experiment is carried out. It is demonstrated that the received feedback power increases from -66 dBm to -44.8 dBm monotonically when Tx transmit power varies from 15 dBm to 30 dBm, which proves an effective solution for compact WPT terminal.

Intelligent reflecting surface empowered WPCN system over generalized κ−μ$$ \kappa -\mu $$ fading channels: Performance analysis and optimization

AbstractIntelligent reflecting surfaces (IRS), which dynamically modify the incident electromagnetic wave propagation characteristics, are appealing as a potential candidate to improve the spectral and energy efficiency of future wireless communication networks. In this paper, we investigate the performance of an IRS‐enabled wireless powered communication network (WPCN), which consists of a dedicated power source (PS), an energy‐constrained wireless device (WD), and a data access point (DAP). Due to energy limitations, WD first performs energy harvesting (EH) operation through the radio‐frequency (RF) signal supplied by the PS and then uses this energy to transmit its information to DAP. In this system setup, an IRS module is employed at both PS and DAP, respectively, in order to enhance the wireless energy transfer and wireless information transfer efficiency. For the underlying system model, we develop a unified performance evaluation framework with regard to outage probability, average throughput, effective throughput, and average, by assuming a generalized fading channels. In addition, we also present an asymptotic analysis, under a high signal‐to‐noise ratio assumption, which helps us to understand the system behavior deeply. Furthermore, an optimal EH time duration is developed for the proposed model to achieve maximum system throughput. The numerical simulation results demonstrate that the IRS‐enabled wireless transmission mechanisms for the WPCN system help to boost the overall performance significantly compared to conventional WPCN networks. All the derived numerical results are verified with Monte‐Carlo simulation results.

A Virtual Projection-Based Incentive Routing Protocol for Mobile PFNs in Wireless Sensor Networks

The current Wireless Sensor Network (WSN) lacks the desired power owning to the non-availability of the power source. The challenge posed in the current scenario is conserving power for effective data transfer, which is seldom achieved. Added to the owes is the evolving technological innovations where the physical size of the Packet Forwarding Nodes (PFNs) is also reduced along with its power source, thereby reducing the power available to the system and making it inefficient. The existing methodology employed in monitoring the parameters used in Epidemic Algorithm (EA) and Incentive Compatible Routing Protocol (ICRP) protocols which are power guzzlers, the power available for data transfer is greatly reduced making the entire system inefficient. This paper attempts to mitigate the challenges posed by the EA & ICRP, the proposed protocol, “Incentive Routing Protocol with Virtual Projection (IRPVP)”, employs a Relay Sensing Node (RSN) which is designed to be distributed in a square cross-sectional area where each node acts as a unique Sensing Point (SP) monitoring each of the essential parameters like energy consumption, vibrant & non-vibrant SPN count, residual energy and routing overhead while still retaining power for data transfer since the RSN is connected to a dedicated power source. In IRPVP protocol, each packet of a node is subdivided into fragments that are designed to have fixed or variable lengths depending upon the application. Each of these packets is sent over multiple Packet Forwarding Nodes (PFNs) towards the data center. The selection of PFNs in the path is based on their trust levels like meeting probability, computation of residual energy, data weight, and security value. Special PFNs are placed in the network and are entrusted to deliver the packets to the data center without data loss during transmission. The result of the IRPVP protocol Vis-à-Vis the EA & ICRP protocol, backed by the simulation results proves that the IRPVP protocol is better in data handling and is more efficient.

Performance analysis of wireless-powered cognitive radio networks with ambient backscatter

Ambient backscatter is a promising wireless communication technique where low-power users communicate with each other without any dedicated power source. These communicating users transmit their information by reflecting ambient radio-frequency (RF) signals. In this paper, we propose an ambient backscatter communications-assisted wireless-powered underlay cognitive radio network (CRN). The proposed CRN consists of a single primary transmitter (PT) and multiple primary receivers (PRs), secondary transmitters (STs), and secondary receivers (SRs). For efficient utilization of radio resources, the STs in the proposed scheme dynamically adopt either harvest-then-transmit mode or backscatter mode. Furthermore, PRs cooperate with STs to select an appropriate mode for their communication with SRs. To evaluate the performance of our proposed scheme, we conduct system-level simulations. Numerical results show that the performance of the secondary system can be improved in terms of throughput with minimum effect on the communication of primary users.

The Use of a Small Single Fuel Cell to Feed a 10-H Superconducting Coil

In this paper, we propose to replace the usual dedicated electronic power supplies of superconducting coil, which are in most cases a huge volume and/or a low energy yield, by a 100 cm² single proton exchange membrane fuel cell (PEMFC). Indeed, fuel cells are electrochemical converters which can be considered as DC low voltage electrical source. Preliminary investigations led with a single proton exchange membrane fuel cell (PEMFC) could evidence the behavior as a DC current source, in which the current is directly controlled by the hydrogen flow rate. In a first step, we highlighted the feasibility by supplying a small superconducting coil, with an inductance value of 4 mH by means of a single PEMFC and proved that dedicated power source can be replaced by fuel cell. The second step is to feed a superconducting coil with higher inductance, 10 H, as presented in the present work.

PEM single fuel cell as a dedicated power source for high-inductive superconducting coils

In practice, the voltage of a hydrogen–oxygen fuel cell is around 1 V at open circuit and from 0.6 V to 0.7 V at full rated load and it can be considered as a low-voltage energy source. Moreover, preliminary investigations undertaken on a single proton exchange membrane fuel cell (PEMFC) highlighted its behavior as a DC current source, that can be directly controlled by the H2 flow rate when the operating point is at very low voltage. In this paper, we present an innovative application of PEMFC that relies on taking advantage of both low voltage level and current source operating mode to feed a high inductive superconducting coil. Such a coil has no resistance and among others, is very sensitive to current ripples. Thus, specific power supplies are designed to feed them but they exhibit in most cases a huge volume and/or a low energy yield. Connecting a superconducting coil to a PEMFC implies to operate in short-circuit, which is an unusual use of PEMFC. To this end, requirements of such an application are defined, by making use of a PEMFC electrical model based on a 1D analog representation of mass transport phenomena. This model, that enables to take into account the influence of gas supply conditions, notably diffusion limit operation, is directly implemented in a standard simulation software used in electrical engineering. Then, simulation results and experimental results obtained by supplying a 10 H superconducting coil cooled by liquid helium by means of a single 100 cm2 PEMFC are compared and discussed.

Creation of a transcatheter fenestration in children with failure of Fontan circulation: Focus on extracardiac conduit connection.

We report our experience with a transcatheter technique to bypass the lung and to thus improve single-ventricle preload and reduce venous congestion in Fontan patients. In the absence of a dedicated power source to serve the pulmonary circulation and a significantly elevated transpulmonary pressure gradient, fenestration of the Fontan circulation is an option to improve hemodynamics in patients by relieving excessive systemic venous pressure. From 2005 to 2011, 22 transcatheter fenestrations were performed without any major complications in 19 patients (median age 3.2 years, interquartile range (IQR) 2.7-3.7 years)) with failing Fontan circulation and exceeding systemic venous pressure. In 16 patients, the procedure was performed for acute postoperative failure 1-24 days after surgery. After perforation of the conduit and atrial wall by a Brockenbrough needle and gradual balloon dilation, premounted stents were expanded to create a diabolo configuration with flaring stent edges, leaving a slight but definitive central waist. The procedure resulted in regression of pleural effusions and a significant decrease in systemic venous pressure. Clinical improvement was observed in 16 of the 19 treated patients. Follow-up demonstrated sustained fenestration in 85% of treated patients for at least 24 months. Transcatheter creation of a Fontan fenestration is a safe approach despite the anatomic gap between the extracardiac conduit cavity and the atrial wall. Stent implantation allows defining the diameter of the fenestration, reduces spontaneous occlusion, and ensures sustained clinical improvement.

Dorsal Column Steerability with Dual Parallel Leads using Dedicated Power Sources: A Computational Model

In spinal cord stimulation (SCS), concordance of stimulation-induced paresthesia over painful body regions is a necessary condition for therapeutic efficacy. Since patient pain patterns can be unique, a common stimulation configuration is the placement of two leads in parallel in the dorsal epidural space. This construct provides flexibility in steering stimulation current mediolaterally over the dorsal column to achieve better pain-paresthesia overlap. Using a mathematical model with an accurate fiber diameter distribution, we studied the ability of dual parallel leads to steer stimulation between adjacent contacts on dual parallel leads using (1) a single source system, and (2) a multi-source system, with a dedicated current source for each contact. The volume conductor model of a low-thoracic spinal cord with epidurally-positioned dual parallel (2 mm separation) percutaneous leads was first created, and the electric field was calculated using ANSYS, a finite element modeling tool. The activating function for 10 um fibers was computed as the second difference of the extracellular potential along the nodes of Ranvier on the nerve fibers in the dorsal column. The volume of activation (VOA) and the central point of the VOA were computed using a predetermined threshold of the activating function. The model compared the field steering results with single source versus dedicated power source systems on dual 8-contact stimulation leads. The model predicted that the multi-source system can target more central points of stimulation on the dorsal column than a single source system (100 vs. 3) and the mean steering step for mediolateral steering is 0.02 mm for multi-source systems vs 1 mm for single source systems, a 50-fold improvement. The ability to center stimulation regions in the dorsal column with high resolution may allow for better optimization of paresthesia-pain overlap in patients.

Dorsal Column Steerability with Dual Parallel Leads using Dedicated Power Sources: A Computational Model

In spinal cord stimulation (SCS), concordance of stimulation-induced paresthesia over painful body regions is a necessary condition for therapeutic efficacy. Since patient pain patterns can be unique, a common stimulation configuration is the placement of two leads in parallel in the dorsal epidural space. This construct provides flexibility in steering stimulation current mediolaterally over the dorsal column to achieve better pain-paresthesia overlap. Using a mathematical model with an accurate fiber diameter distribution, we studied the ability of dual parallel leads to steer stimulation between adjacent contacts on dual parallel leads using (1) a single source system, and (2) a multi-source system, with a dedicated current source for each contact. The volume conductor model of a low-thoracic spinal cord with epidurally-positioned dual parallel (2 mm separation) percutaneous leads was first created, and the electric field was calculated using ANSYS, a finite element modeling tool. The activating function for 10 um fibers was computed as the second difference of the extracellular potential along the nodes of Ranvier on the nerve fibers in the dorsal column. The volume of activation (VOA) and the central point of the VOA were computed using a predetermined threshold of the activating function. The model compared the field steering results with single source versus dedicated power source systems on dual 8-contact stimulation leads. The model predicted that the multi-source system can target more central points of stimulation on the dorsal column than a single source system (100 vs. 3) and the mean steering step for mediolateral steering is 0.02 mm for multi-source systems vs 1 mm for single source systems, a 50-fold improvement. The ability to center stimulation regions in the dorsal column with high resolution may allow for better optimization of paresthesia-pain overlap in patients.

Discussion of "Direct harmonic analysis of the voltage source converter"

The author [1] must be congratulated for the presented method for the closed-form solution of the problem of the determination of harmonic interactions in voltage source converters (VSCs) with emphasis on dc voltage ripple determination. The dc supply is assumed to be an ideal voltage source in Section II and then it is replaced by a capacitor in Section III to derive the equations for the complete harmonic analysis. Taking into consideration that there are several applications where the VSC is supplied by an ac/dc converter connected to the power grid (as for all industrial drives using an induction motor) or to a dedicated power source (such as for STATic COMpensator (STATCOM) solutions with battery or superconductive storage system), it would be of interest to observe the analysis of the dc link voltage harmonics and of the interaction of these harmonics with those produced by the supplying rectifier. Another point which could deserve more attention is the analysis of modulation strategies other than pulse-width modulation (PWM), such as those considered in [2]. A comment from the author is appreciated also on the approach to the analysis of random modulations (like those reported in [3]–[5] and considered in [2]), which are very attractive to reduce harmonic pollution on the inverter load by spreading the energy content of commutation disturbance on a wider frequency range. REFERENCES