Miracle-dz/UniFAR-FTUs huggingface dataset:
The Effect of Pulsed Current on the Performance of Lithium-ion Batteries

The pulsed current is considered to improve the performance of the Lithium-ion (Li-ion) battery. However, the effect of the pulsed current on Li-ion battery performances is inconclusive at present. In this paper, a battery cell was charged by applying a 0.05 Hz pulsed current. Different duty cycles, the current-rates (C-rates), and ambient temperatures were considered in order to obtain a clear impact of the pulsed current on the battery performance during charging. Compared with the constant current, the pulsed current can improve the charging capacity and decrease the maximum rising temperature by 30.63% and 60.3%, respectively. The results obtained were used for the parameterization of a capacity model and charging time model, which are able to express both the capacity and charging time at different charging conditions of the Li-ion battery cell.
Improved Sensorless Control Method for Permanent Magnet Synchronous Machines Considering Resistance Asymmetry and Temperature Variation

This paper aims to improve the sensorless control performance for permanent-magnet synchronous machines (PMSMs) under resistance asymmetry. The improved sensorless method can eliminate the undesired 2nd order fluctuation in position and speed estimation with the help of sequence component extractor (SCE) while the DC offset position error caused by asymmetric resistance and temperature variation can be compensated by applying a novel pulse injection method. Experimental and simulation results are provided to validate the proposed methods.
Adaptive PR and BBO Based Control Strategy of Wind-Solar Integrated Standalone Microgrid for Residential Application

The off-grid village electrification is made viable by utilizing the full potential offered by renewable energy sources (RESs). Integrating more than one resource i.e. wind and solar, offers self-sufficiency of power due to their complementary nature. The intermittency issues raised by RESs are overcome by using a battery as the storage. The battery reduces the uncertainty during demand rise, power deficiency and overloading with its faster response than diesel generators and micro-turbines. This work deals with the wind energy/solar photovoltaic (PV)/battery energy storage (BES) operating in coordinated manner to meet the high power residential loads at village scale. For the required speed regulation of a wind turbine driven generator, the traditional proportional integral (PI) controller is replaced by evolution inspired biogeography based optimization control (BBO) based PI controller. The relevant issues identified by a use of fixed gain PI controller such as, unsuitable regulation due to incorrect tuning are addressed by the use of BBO tuned speed controller providing fine-tuning of the weighting factors. Whereas, in the voltage control, the performance degradation issue of PI controller while dealing with AC quantities, is dealt with adaptive proportional resonant (PR) controller along with disturbance observer based phase locked loop (DO-PLL). The DO control filters the load current component and improves the power quality at point of common coupling (PCC). The battery is deployed through a bidirectional converter, acts as a residential storage for backing up the power firming RESs production. Performance improvement obtained from a laboratory developed test setup verifies the microgrid effectiveness at RESs generation variability and load changes.
Decoupled Active and Reactive Power Control without PLL Requirement for Differential Buck Converter

This paper presents a decoupled active and reactive power control for the differential buck converter. This control does not require phase locked loop (PLL) for synchronization. Also, it achieves active and reactive power control in a simple single control loop structure. The differential buck converter has the capability to compensate the double line frequency power ripple without relying on additional hardware. Particularly, the Common Mode (CM) operation is used for active double line frequency power ripple absorption. Whereas, the Differential Mode (DM) operation is used as an active and reactive power exchanging port between the converter and the grid at the point of common coupling (PCC). The motivation behind this paper proposal are: (i) to avoid PLL induced instabilities, especially, when connecting the differential buck converter with weak grid, and (ii) direct active and reactive power control for the differential buck in a single loop control. The theoretical analyses are verified with a 5 kW converter with only 50 μF decoupling capacitor connected to a weak grid.
Review and Comparison of Resonant DC-DC Converters for Wide-Output Voltage Range Applications

In a wide-output voltage range application, the resonant converter is required to achieve high efficiency and narrow switching frequency over a wide output voltage range. Several resonant topologies have been proposed to fulfill these requirements. These topologies have been stated in this paper. A review and comparison of DC-DC resonant converters for wide-output voltage range application are presented in this paper. Different methods are used in the reported topologies, such as multi-phase bridge, dual half-bridge, and multi-secondary windings. To help providing full understanding of advantages and drawbacks of these different topologies, this paper will present a comprehensive review of these topologies and provide detailed performance comparison.
Trade-offs Between Gate Oxide Protection and Performance in SiC MOSFETs

The reliability of gate oxides in SiC MOSFETs has come under increased scrutiny due to reduced performance under time dependent dielectric breakdown and increased threshold voltage instability. This paper investigates how 10% gate voltage (VGS) derating in SiC MOSFETs can be implemented with minimal impact on loss performance. Using experimental measurements and electrothermal simulations of power converters, the trade-off between reduced VGS and conversion loss is investigated. It is shown that 10% VGS de-rating increases the ON-state resistance by 10% and the turn-ON switching energy by 7% average while the turn-OFF switching energy is unaffected. The low temperature sensitivity of the ON-state losses in SiC MOSFETs can be exploited since the rise in junction temperature due to VGS derating is marginal, unlike Si devices where ON-state resistance rises significantly with temperature. The load current and switching frequency influences the effectiveness of VGS derating. It is also shown that reducing the gate drive output impedance can compensate for VGS derating at high switching frequencies, with reduced total loss penalization. This may be important for protecting the gate oxide and enhancing its reliability.
Verification of Iron Loss Affected by Secondary Frequency in Multi-core Transformer for Frequency Multiplying Circuit

This paper verifies the iron loss affected by the secondary frequency in the multi-core transformer for the frequency multiplying circuit. In the frequency multiplying circuit, the secondary frequency component also flows through the primary winding although the transformer is excited by the primary switching frequency, which is one-fifth of the secondary frequency. However, the influence of the secondary frequency to the iron loss of the multi-core transformer in the frequency multiplying circuit has not discussed sufficiently. In this paper, three conditions including a no-load test, a resonant test where the inductance of the secondary side is dominant, and a resonant test where the inductance of the primary side is dominant, are demonstrated in order to verify the influence of the secondary frequency to the exciting voltage and the magnetizing current, that is, the influence of the voltage drop on the primary winding to the iron loss. The iron loss of Mn-Zn ferrite (PC40, TDK) is measured by drawing B (magnetic flux density)-H (magnetic field intensity) curves under the switching frequency is around 200 kHz and the secondary frequency is around 1 MHz. Experimental results verified the increment of the iron loss is 5.1% when the inductance of the secondary side is dominant to the total resonant inductance compared to that in the no-load test. In addition, it is confirmed that the increment of the iron loss is increased by the amplitude of the secondary current. On the other hand, experimental results verified that the secondary frequency significantly affects to the iron loss when the inductance of the primary side is dominant to the total resonant inductance because the voltage drop due to the primary winding’s parameters and the secondary frequency component in the primary current occurs. The increment of the iron loss is 35.9% compared to that in a no-load test. From these observations, this paper indicates that placing the resonant inductance at the secondary side is effective for suppressing the influence of the secondary frequency to the iron loss of the multi-core transformer for the frequency multiplying circuit.
Improved Rotor Bar Structure in High-Voltage High-Power Induction Motors to Eliminate Local Thermal Spot and Avoid Broken Bar faults

Due to complex harmonic field effect and frequently starting operation conditions, broken bars are the most common fault in practice, for instance, in the auxiliary motor systems in the power plant. To solve this problem, this paper proposes an improved rotor slot structure of large-power and high-voltage induction motors in the re-manufacturing process, for eliminating the local thermal spot and avoiding broken bars. This structure adopts a novel harmonic field slot to eliminate the skin effect caused by high-frequency harmonic fields, and the optimal design of slot size, opening width, and height, air-gap length based on finite element analysis (FEA) are performed to verify its effectiveness. Experimental validation is performed on a re-manufactured 6-kV 1600-kW induction motor in a thermal power plant in China. The results show that the presented design structure can eliminate the local thermal spot in rotor side and the measured thermal distribution in the surface of stator cooler can also be reduced by 18°C. The achievement of this paper can provide the technical support for countermeasure of broken bar fault in large-power and high-voltage induction motors.
Real-time Upper Body Reconstruction and Streaming for Mixed Reality Applications

In view of the challenges of real-time 3D reconstruction and transmission, the research on tele-immersion systems has been quite intense. We present an end-to-end, realtime 3D reconstruction system of the human body’s upper part in mixed reality applications, implemented with the use of a single depth camera on the capture side, whereas no special setup is required. Our system captures the scene, extracts the user’s point cloud and by quantizing it, achieves real-time mesh generation and streaming. This system, together with the appropriate virtual (VR) or augmented (AR) reality equipment, creates a sense of a more direct, face-to-face communication, as if both users were in the same environment.
Shift-Limited Sort: Optimizing Sorting Performance on Skyrmion Memory-Based Systems

Modern nonvolatile memories (NVMs) are widely recognized as energy-efficient replacements of classical memory/storage media, such as SRAM, DRAM, and mechanical hard disk. Among the popular NVMs, the skyrmion racetrack memory (SK-RM) is well known for its high storage density and unique supports of insert/delete operations. However, the existing algorithms designed for classical media might experience serious performance degradation when working on the SK-RM, due to the distinct characteristics of SK-RM. Thus, the existing algorithms should be redesigned to adapt to the brand-new memory model based on the SK-RM, so as to fully reveal the potentials of SK-RM. In particular, many existing algorithms tend to access the in-memory data in a random-hopping fashion, which generates many time-consuming shift operations of SK-RM. It is therefore crucial for the existing algorithms to eliminate unnecessary shift operations of SK-RM to boost the performance of the algorithms. In many modern applications, such as multimedia and data analysis, it is a common operation to process two or more arrays/vectors of data to perform certain computation tasks. In the arrays/vectors, an appropriate data placement strategy is critical for avoiding unnecessary shift operations of SK-RM. The observation thus motivates this work in proposing a <italic>recursive back-to-back</italic> data placement manner to effectively reduces the shift operations of SK-RM. To demonstrate the back-to-back data placement, we take sorting algorithms as a case study, and propose a novel <italic>shift-limited sorting algorithm</italic> for SK-RM. Analytical studies show that the shift-limited sort effectively enhances the time complexity of classical merge sort from <inline-formula> <tex-math notation="LaTeX">$\mathcal {O}(dn\lg n)$ </tex-math></inline-formula> to <inline-formula> <tex-math notation="LaTeX">$\mathcal {O}(n\lg n)$ </tex-math></inline-formula>, where <inline-formula> <tex-math notation="LaTeX">$d$ </tex-math></inline-formula> is the bit distance between adjacent access ports on the nanotracks of the SK-RM. After that, the efficacy of the proposed shift-limited sort is then verified by experimental studies, where the results are encouraging.
Dual Side Control of Wireless Power Transfer with Mutual Inductance Estimation

In this paper, with two H-bridge inverters like a dual active bridge, a dual side controlled wireless power transfer (WPT) system is proposed, especially without communication. In conventional dual side-controlled communication-less WPT studies, load condition is unknown at the primary side inverter. So, the primary side inverter usually operates in the full load condition. This paper proposes a way for controlling the primary side inverter according to load conditions with the estimation of secondary side inverter information. For the way, the estimation procedure of mutual inductance considering the change of self-inductance at the primary side is proposed. The proposed method improves efficiency at the overall load condition, which is verified with the experimental results.
A Dynamic Efficiency Optimization Method under ZVS Conditions in the Series-Series Type Wireless Power Transfer System

In this paper, the conditions for achieving ZVS of all MOSFET-based switches are presented and discussed. Moreover, a novel joint control with variable ZVS angles (JC-VZA) is proposed to achieve the required output voltage and ZVS of all switches simultaneously. Next, based on JC-VZA, a dynamic efficiency optimization method is also proposed to make the system achieve the minimum power loss. Finally, a 500-W experimental prototype is built. With the proposed JC-VZA for dynamic efficiency optimization, the WPTS can not only achieve a very high overall transfer efficiency, but also obtain good dynamic performances.
Normal-Based Flower Pollination Algorithm (FPA) for Solving 3D Point Set Registration via Rotation Optimization

Compared with the registration methods based on local optimizations, the heuristic registration methods are less sensitive to the initial position, and a reasonable bound range is essential to ensure the registration validity. In practice, compared with a rotation bound range, which is periodic, the setting of the translation range is more difficult and manual interventions required, especially when the initial position is complex. Moreover, it has yet to be discussed in past research. Therefore, a normal-based registration method based on the flower pollination algorithm is proposed in this paper, in which only rotation parameters ( $r_{x},r_{y},r_{z}$ ) are considered. In our method, the point correspondences are guided by their normal due to their invariance to position translation. Considering the normal degeneration caused by noise, outliers, and partial overlapping, the Pauta criterion is employed to remove distorted correspondences and acquire reliable translation. Moreover, the population of optimal pollens is guaranteed by the use of the searching radius adjustment and periodic boundary. A number of experiments demonstrate that the proposed method exhibits competitive or better performance in terms of initial position, noise, outliers and partial overlapping. Furthermore, a real quality inspection is also implemented to confirm the availability and superiority of the proposed method in the manufacturing process.
High-Gain Four-Phase DC–DC Converter with Current and Voltage Self-Averaging Feature

A high-gain four-phase DC–DC converter is proposed, whose high voltage gain characteristic is suitable for applications such as photovoltaic generations, electric vehicles, energy storage system and so on. The proposed converter is improved from the traditional four-phase interleaved parallel DC-DC converter and has only three more capacitors than the traditional converter. The proposed converter has the voltage gain of about four times that of the traditional converter. When the output voltage is the same, the proposed converter has lower switching voltage stresses than the traditional converter. What’s more, the proposed converter has current self-averaging and voltage self-averaging feature, which can make the proposed converter operating in open-loop controlled state without using inductor current sharing control and capacitor voltage balancing control. These features can also make the proposed converter operating in closed-loop control state only using one current sensor and one voltage sensor, which can save the design cost of hardware control circuit. Switching strategy, operating modes and steady state analysis are analyzed in more detail. Finally, a 300W, 24V-input to 200V-output prototype experiment is implemented.
Vehicle-to-Vehicle Inductive Power Transfer: Design Analysis and Topology Selection

This paper presents an inductive power transfer (IPT) system for vehicle-to-vehicle (V2V) charging applications utilizing an intermediate coil. Two different intermediate coil structures are discussed and compared, which shows that a concentrated winding brings a higher mutual inductance. Furthermore, different matching networks, namely series-series-series (SSS) and LCC-S-LCC, are analyzed for the V2V IPT application. The analysis shows that by properly selecting compensation factors, the LCC-S-LCC topology can provide higher and more stable efficiency than the former counterpart. In addition, power flow analysis has been performed, which shows the relation between transferred power and phase angle between input and output inverter’s voltage. As a result, the phase angle is utilized to control the power flow between the two EVs. PLECS simulations are performed to verify the proposed concept and analysis.
A Lightweight Nonlinear Methodology to Accurately Model Multicore Processor Power

Many power management algorithms demand accurate and fine-grained runtime estimations of dynamic core power. In the absence of fine-grained power sensors, model-based estimations are needed. Such power models commonly approximate the switching activity of logic gates using performance counters while assuming a linear performance counter/power relation at a fixed frequency and voltage. It has been shown that this relation cannot be captured accurately enough with purely linear models and that well-established nonlinear modeling techniques, e.g., polynomial modeling, easily overfit the underlying performance/power relations. Although neural-network-based modeling has shown to accurately capture nonlinear relations, it has a large training and inference overhead which is too high for fine-grained models on core-level and estimation rates in the range of 1–10 kHz. We propose a methodology for nonlinear transformation of specific performance counters to increase power modeling accuracy at constant frequency and voltage with a relatively low overhead for both model generation and run-time application over a linear model. Furthermore, we use least-angle regression (LARS) to determine a ranking of the performance counter inputs for use in linear and nonlinear modeling and show that the transformed performance counters are better suited for power modeling. The generated dynamic power model consisting of a nonlinear transformation block and a linear regression block reduces relative estimation error on average by 4% and in worst-case scenarios by 7% compared to state-of-the-art fine-grained linear power models. Compared to a state-of-the-art polynomial regression model our proposed approach reduces the relative estimation error by 10% in worst-case scenarios.
The Role of Water and Ethanol Molecular Geometry in Goveming the Growth Kinetics of Zno-Nanorods

This paper presents the influence of solvents molecular geometry on the growth mechanism of ZnO nanorods and their morphology. We observed that the wurtzite hexagonal crystal system of ZnO offers a number of interacting sites at different positions for the solvent water and ethanol molecules to influence the aspect ratio of the ZnO nanorods. ZnO nanorods were synthesized individually in water and ethanol on a highly conductive nitrogen incorporated graphene oxide (NGO) substrate. NGO was synthesized by the dual interactions of paraxylylenediamine with GO, which created an abundant quantity of electrophilic and nucleophilic centers to provide an ideal environment for the synthesis of ZnO nanorods. The successful formation of nanorods in water (NGO-ZnO/W) and ethanol (NGO-ZnO/E) was confirmed through high-resolution transmission electron microscopy.
Quantitative Timing Analysis for Cyber-Physical Systems Using Uncertainty-Aware Scenario-Based Specifications

Due to the merits of intuitive and visual modeling of design requirements, unified modeling language (UML) sequence diagrams are widely used as scenario-based specifications in the design of cyber-physical systems (CPSs). However, when more and more CPS products are deployed within an uncertain environment, existing sequence diagram analysis approaches cannot be used to accurately capture and quantify their timing behaviors at an early design stage. To address this problem, this article extends UML sequence diagrams to allow the modeling of stochastic system inputs, message processing time, and network delays, which strongly affect the system timing behaviors. We develop a statistical model checking-based framework that can automatically convert stochastic sequence diagrams into networks of priced timed automata to enable the quantitative analysis under various performance queries. The experimental results of two industrial designs in the railway field demonstrate the effectiveness of our approach.
Characterization of the Thermal Performances of Low-Cost Sub-Fractional Horsepower BLDC Claw-Pole Motor Designs

Automotive auxiliary drives often have to operate over a large temperature range, e.g., between -40 and 135 degrees Celcius. Especially for operation at high ambient temperatures, the understanding of their thermal characteristics is highly important as, e.g., the electromagnetic characteristics of permanent-magnets are strongly temperature-dependent. To this aim, this paper investigates the steady-state and transient thermal performances of different low-cost sub-fractional horsepower single-phase BLDC claw-pole motor designs suitable, e.g., for fan applications. Both numerical and experimental analyses are carried out to determine the parameters of a simple thermal equivalent circuit. The studied claw-pole motor designs show similar thermal performances, which allows all of them to be used in an automotive auxiliary drive system.