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Pricing multi-interval economic dispatch of electric power under operational uncertainty is considered in this two-part paper. Part I investigates dispatch-following incentives of profit-maximizing generators and shows that, under mild conditions, no uniform-pricing scheme for the rolling-window economic dispatch provides dispatch-following incentives that avoid discriminative out-of-the-market uplifts. A nonuniform pricing mechanism, referred to as the temporal locational marginal pricing (TLMP), is proposed. As an extension of the standard locational marginal pricing (LMP), TLMP takes into account both generation and ramping-induced opportunity costs. It eliminates the need for the out-of-the-market uplifts and guarantees full dispatch-following incentives regardless of the accuracy of the demand forecasts used in the dispatch. It is also shown that, under TLMP, a price-taking market participant has incentives to bid truthfully with its marginal cost of generation. Part II of the paper extends the theoretical results developed in Part I to more general network settings. It investigates a broader set of performance measures, including the incentives of the truthful revelation of ramping limits, revenue adequacy of the operator, consumer payments, generator profits, and price volatility under the rolling-window dispatch model with demand forecast errors. [ABSTRACT FROM AUTHOR]

As high-speed railways develop rapidly worldwide, the problems of neutral section and power quality are becoming increasingly prominent. These problems affect the normal operation of the power grid and the electric locomotives. The co-phase power supply schemes were proposed by researchers, which can solve these problems well. Among them, the MMC-based scheme (MMC-5 L) is a representative one. The existing scheme, when applied to the auto-transformer (AT)-fed system which is usually adopted by high-speed railways, needs to install an auto-transformer on the output side. To eliminate the auto-transformer and to obtain the more suitable and superior co-phase power supply schemes to AT-fed system, two improved schemes are proposed in this paper based on the novel MMC-based scheme (MMC-6 L) we proposed before. While establishing the mathematical model, creating the control system, and carrying out simulation verification of the proposed schemes, the proposed schemes are compared with MMC-6 L and MMC-5 L in terms of topological characteristics, control system complexity, power loss, and functionality. The results show that while the proposed schemes can fulfill the functions of the co-phase power supply scheme well like the MMC-5 L and MMC-6 L, they are more suitable and superior for the AT-fed system in terms of control system complexity and power loss. Among them, MMC-5L1CB performs best in power loss, and MMC-4L2CB performs best in control system complexity. [ABSTRACT FROM AUTHOR]

The electric drive power density and fault tolerance capability are of fundamental importance in many applications such as aerospace and traction applications. The modularization and the physical integration of the electric motor and the power converter components can lead to a high power density and a high fault tolerance drive system. The power density of a highly modular and integrated drive based on an axial flux permanent magnet synchronous machine and GaN converter is investigated in this paper. Several power density boosting techniques are provided and investigated using CFD simulations. These techniques incorporate optimization of the converter topology, the geometry of the shared cooling structure of the electric machine and the power converter and optimal selection of the materials in the path of heat transfer from the machine and the power converter to the cooling ambient. The power density of the reference integrated design is increased from 1.12 kW/ $l$ to 2.14 kW/ $l$. The CFD computations are validated by extensive measurements on a modular integrated setup. [ABSTRACT FROM AUTHOR]

Dynamic wireless charging (DWC) is one of the most promising and economical power supply solutions for electric vehicles (EVs), which can address range anxiety and downsize the volume of onboard batteries. To solve the null power phenomenon and transfer power pulsation phenomenon in DWC scheme, this paper proposes a new magnetic coupler array to implement continuous charging and reduce the output power variation. The transmitters are placed with a proper interval to eliminate the adjacent coupling and enlarge the coil array’s effective length. ANSYS Maxwell is utilized to demonstrate the finite element analysis (FEA) of the DWC system. A larger receiver coil is designed to significantly mitigate power pulsation and increase the magnetic coupling as the receiver moves along the array. With the well-designed receiver coil, the output power pulsation is $\pm$ 1.52 $\%$. For the high-power capacity scenario, a multilevel connected DC-DC converter is designed on the receiver side to regulate the transfer power. Besides, a passivity-based control (PBC) is developed for the receiving DC-DC converter based on the Euler-Lagrange (EL) model, and a current sharing compensator is employed to balance each phase inductor current. Finally, a 500- $\text{W}$ prototype is constructed, and experimental results are represented to validate the proposed optimized coil array and the proposed PBC method. [ABSTRACT FROM AUTHOR]

Autotransformer (AT) traction network (ATN) expands widely with the rapid development of high-speed railway (HSR). The fault occurrence in ATN will affect the safety and reliability of power supply for electric multiple units (EMUs). However, due to the nonlinear relationship between measured impedance and distance, the accuracy and efficiency of the fault location for ATN is facing serious challenges, especially with the diverse fault types and operation modes. In this paper, the general circuit topology of subsections is given and the characteristics of voltage distribution are analyzed according to the impedance matrix of ATN. Through the decoupling method, a comprehensive equivalent model adopting composite impedance is established, which can illustrate a series of characteristics for all fault types. Furthermore, the fault-location method is proposed to express the mapping between the fault position and the relevant electrical quantities for the subsection, and then a reasonable compensation for the effect of mutual impedance between faulty and non-faulty subsections is provided to improve the accuracy. Consequently, the multi-terminals synchronous information is employed for unified fault-location for ATN. Case studies including simulation and field testing have verified that the method is accurate and quite robust to various fault scenarios. [ABSTRACT FROM AUTHOR]

Tokamak device requires a very high current power supply from the local power distribution sources to the targeted magnets such as toroidal field (TF) coils and poloidal field (PF) coils. This paper presents a preliminary design of a 30-m/1-kV/10-kA low voltage direct current (LVDC) superconducting cable for the potential in Tokamak applications. The outer diameter of the DC cable is 122.41 mm, and the pressure drop of liquid nitrogen (LN2) in the inner and outer channels is about 6.59 kPa. The flow velocity of inner and outer LN2 channels are 0.5 m/s and 0.25 m/s, respectively. The temperature rise of the entire cable was designed to be less than 5 K, which enhances the electricity supply safety and reliability. These preliminary design lays some technical bases for achieving high current and low loss power transmission. The designing results show that the LVDC superconducting cable has significant potentials for Tokamak applications compared with conventional copper cables. [ABSTRACT FROM AUTHOR]

This paper combines the use of multi-phase configurations and current harmonic injection methods to achieve significantly improved performance for doubly salient synchronous reluctance machines (DS-SRMs). In order to understand the torque production mechanism of multi-phase DS-SRMs with current harmonic injection, some general analytical torque models have been developed. The models are based on Fourier Series analysis of self- and mutual-inductances. It has been established that with current harmonic injection, the torque ripple of both 5-phase and 6-phase DS-SRMs can be significantly reduced and the average torque can be enhanced. It contrast, harmonic injection always has a detrimental impact on 4-phase machines. The investigations of losses and dynamic performance with current harmonic injection for multi-phase machine have also been carried out and demonstrated that the proposed method can improve the efficiency in constant torque region and maintain comparable performance to fundamental current supply in the flux weakening region. Experimental validation based on single layer, 6-phase, DS-SRM has been performed. [ABSTRACT FROM AUTHOR]

This paper provides an overview of hyperloop technologies, including a brief discussion of key components of a hyperloop system that determine the electric power requirements as a function of time. At-scale hyperloop systems do not yet exist, so a model was used to generate a set of load profiles for conceptual hyperloop realizations at four locations in the United States: two systems in California and one each in Colorado and Ohio. In all four cases, the modeled hyperloop load profiles included pulses in both active and reactive power. Grid modeling was performed to estimate the grid impacts and for discussing grid integration challenges. The paper discusses how energy storage systems might be used to eliminate the pulsating load characteristics or significantly reduce it to accommodate current grid planning guidelines. [ABSTRACT FROM AUTHOR]

Pricing multi-interval economic dispatch of electric power under operational uncertainty is considered in this two-part paper. Part I investigates dispatch-following incentives for generators under the locational marginal pricing (LMP) and temporal locational marginal pricing (TLMP) policies. Extending the theoretical results developed in Part I, Part II evaluates a broader set of performance measures under a general network model. For networks with power flow constraints, TLMP is shown to have an energy-congestion-ramping price decomposition. Under the one-shot dispatch and pricing model, this decomposition leads to a nonnegative merchandising surplus equal to the sum of congestion and ramping surpluses. It is also shown that, comparing with LMP, TLMP imposes a penalty on generators with limited ramping capabilities, thus giving incentives for generators to reveal their ramping limits truthfully and improve their ramping capacities. Several benchmark pricing mechanisms are evaluated under the rolling-window dispatch and pricing models. The performance measures considered are the level of out-of-the-market uplifts, the revenue adequacy of the system operator, consumer payment, generator profit, level of discriminative payment, and price volatility. [ABSTRACT FROM AUTHOR]

This paper presents a methodological framework to evaluate the resilience, with the primary focus on performance degradation, of levee-protected electric power networks to flooding in a changing climate. To this end, a multi-disciplinary framework is established by integrating climate science, hydrology, and electric power network analysis. The framework quantifies the effect of climate change on flood hazard levels in a levee-protected area and the subsequent changes in the resilience of the electric power network. In the first step, the changes in the exposure of levee-protected regions to flooding hazard in a warming climate are calculated. Then, the probabilities of failure of power network components due to flooding under current and projected future climate are determined. Finally, the power system resilience index is used to assess the system resiliency for pre-flooding (baseline), historic flooding, and two projected future flooding scenarios. For demonstration, the proposed framework is applied to a levee-protected area in Northern California. The IEEE 118-bus standard test system is employed to represent the power network in the study area. Results reveal that climate change can considerably decrease the system resilience of the levee-protected electric power network. The findings of this study can contribute towards more resilient power network systems under a changing climate. [ABSTRACT FROM AUTHOR]

Globally,wind power plants (WPPs) installations are dramatically increasing, leading to a large-scale integration into the power grids. Huge endeavors are devoted to achieving an efficient operation of WPPs. This paper offers a novel chaotic-billiards optimizer (C-BO) algorithm to properly design the fuzzy logic control (FLC) strategy for stability enhancement of grid-integrated WPPs. The C-BO algorithm has distinct features such as simple construction, low numbers of parameters required to design, high convergence speed, and low computational burden. The permanent-magnet synchronous generator (PMSG)-based WPP is interlinked into the electric power grid through power converters. A cascaded FLC approach, which is optimally fine-tuned by the C-BO, is offered as the control methodology for these converters. The C-BO algorithm fine-tunes the gain factors of multiple FLCs at a rapid convergence speed. A simulation-based optimization approach is applied, in which the integrated square error criterion is chosen as an objective function. For the sake of preciseness, the PMSG-based WPP is connected to the IEEE 39-bus New England test system. The effectiveness of the optimal FLC using the C-BO algorithm is compared with that achieved using the water cycle algorithm-based optimal FLC, the genetic algorithm-based optimal FLC, and the marine predator algorithm-based optimal proportional-integral controller, taking into account severe grid disturbances. Moreover, real wind speed measured data captured from Zaafarana Station in Egypt are extensively performed in the system studies. The validity of the offered control approach is widely verified by the simulation analyses using the MATLAB/Simulink environment. [ABSTRACT FROM AUTHOR]

This paper presents a suite of analytics that are proposed to be embedded in next-generation smart sensors in electric power grids. The proposed analytics take the electrical signals as the input and unlock the full potential in signal processing and machine learning for real-time event detection and classification. Meanwhile, a robust synchrophasor estimation mechanism is housed within the proposed sensor technology that will be triggered following a detected event and guides on the adaptive selection of the best-fit (most accurate) synchrophasor estimation algorithms at all times. Embedding such analytics within the sensor and closer to where the waveforms are captured, the proposed distributed intelligence solution technology mitigates the potential risks to communication failures and latencies as well as malicious cyber threats. Our experiments demonstrate that the introduced scheme achieves improved quality of measurements with a promising event detection and classification accuracy, collectively resulting in enhanced online situational awareness in modern power grids. [ABSTRACT FROM AUTHOR]

A realistic steering feel is one of the key elements to guarantee fidelity on a driving simulator in general, and in particular to replicate on-centre vehicle handling. This requires precise modelling of the steering dynamics, a high bandwidth control loading system, and coupling of virtual and physical components in agreement with computational requirements and hardware limitations. For such a coupling, the common approach position-based control uses the measured signals of steering wheel angle and steering rate as inputs to the steering system model. This paper proposes an alternative torque-based control scheme using steering torque as an input to the steering system with additional compensation. Torque-based control was designed and evaluated in conjunction with detailed electric power steering models including state-of-the-art friction models, a neuromuscular driver model, and two driver-in-the-loop experiments in a high-end driving simulator. The objective analysis performed by means of the neuromuscular driver model reveals that the driver applies less impedance i.e. the driver is less stiff on a driving simulator when steering feedback is provided with the torque-based control compared to the position-based control. The investigations demonstrate that torque-based control reduces haptic response delay and vibrations caused by friction modelling compared to position-based control. The driver-in-the-loop experiments show significant objective effects on steering performance and subjective evaluation of fidelity and effort. We conclude that the proposed approach closes the vehicle-driver loop with more realism in a driving simulator. [ABSTRACT FROM AUTHOR]

Electric power grids regularly experience uncertain fluctuations from load demands and renewables, which poses a risk of violating operational limits designed to safeguard the system. In this paper, we consider the robust AC OPF problem that minimizes the generation cost while requiring a certain level of system security in the presence of uncertainty. The robust AC OPF problem requires that the system satisfy operational limits for all uncertainty realizations within a specified uncertainty set. Guaranteeing robustness is particularly challenging due to the non-convex, nonlinear AC power flow equations, which may not always have a solution. In this work, we extend a previously developed convex restriction to a robust convex restriction, which is a convex inner approximation of the non-convex feasible region of the AC OPF problem that accounts for uncertainty in the power injections. We then use the robust convex restriction in an algorithm that obtains robust solutions to AC OPF problems by solving a sequence of convex optimization problems. We demonstrate our algorithm and its ability to control robustness versus operating cost trade-offs using PGLib test cases. [ABSTRACT FROM AUTHOR]

The renewable energy-based hydrogen production can lead to the integrated electric power and hydrogen system (IPHS) and offer a pathway to a sustainable energy utilization. Hydrogen is mainly transported via hydrogen tube trailers (HTs), making the hydrogen energy system (HES) operation quite different from those of other energy technologies. This paper proposes an optimal IPHS operation strategy which utilizes HT for transportation. The proposed strategy coordinates hydrogen generation, transportation, and storage stages considering constrained operations of electric power system (EPS), transportation system, and variable renewable energy. The proposed solution method is based on the alternating direction method of multipliers (ADMM) in which HES and EPS constraints are managed individually and the respective solutions are coordinated accordingly. The case studies using the modified IEEE-RTS79 have verified the validity of the proposed IPHS model and its solution method and confirmed the necessity of considering HES in enhancing the EPS operation. The synergies between EPS and HES are studied via numerical examples and the impact of the flexibilities in hydrogen generation, transportation and demand are highlighted. [ABSTRACT FROM AUTHOR]

Due to limited amplitude and controlled phase of current supplied by inverter-interfaced renewable power plants (IIRPPs), the IIRPP-side distance protection of lines connected to IIRPPs fails to detect the fault location accurately, so it may malfunction. The composite sequence network of a line connected to an IIRPP during asymmetrical faults is analyzed, and an adaptive distance protection based on the analytical model of additional impedance is proposed in this study. Based on open circuit property of negative-sequence network at the IIRPP-side, the equivalent impedance of power grid and current flowing through fault point are calculated in real-time using local measurements, which are substituted into the analytical model of additional impedance to calculate fault location. In the case of negative-sequence reactive current injection from IIRPPs during asymmetrical faults, the error of calculating fault point current from local measurements is analyzed and corrected to ensure reliability of the proposed protection. The proposed protection alleviates the effect of fault resistance in a system with weak sources. In addition, the proposed protection can adapt to different grid codes (GCs), the operation mode change of the power grid, and the capacity change of the IIRPP. PSCAD/EMTDC test results verify the effectiveness of the proposed protection. [ABSTRACT FROM AUTHOR]

An uninterruptable wireless power supply is developed for a left ventricular assist device (LVAD), which is an implanted, electrically driven centrifugal pump used to treat advanced heart failure pathologies. The LVADs are currently powered through a cable driveline (DL) that exits the patient's body through the skin. Here, an innovative uninterruptable power supply is presented, based on a hybrid wireless/wired architecture: the electric power of 10 W is transferred by the near field wireless power transfer technology operating at 300 kHz, from outside the human body to an implanted subcutaneous receiver, and then by an internal cable to the LVAD. A significant improvement of the subcutaneous receiver is here proposed, based on the integration in the receiving coil of a battery pack providing the following benefits: no-break power supply for the LVAD; peak load management; enhanced system reliability; elimination of DL infection; enhancement of patient's quality of life. The proposed system is first designed and optimized, then a demonstrator is made and tested in a laboratory using the latest LVAD generation. The measured coil currents are used as sources for dosimetric analysis to assess the compliance of the system with the electromagnetic field safety and thermal regulations. [ABSTRACT FROM AUTHOR]

The energy hub (EH) is an essential part of the energy conversion supply process, which integrates multienergy forms to improve energy efficiency effectively. A multiobjective optimization model, including exergy loss and operation cost, is established to balance the efficiency of energy utilization and cost. Due to EH and users being connected by a thermal network, a thermal network model that considers the time delay and loss is established. An interaction framework based on the bargaining game theory is proposed to realize the coordination between EHs and heat station (HS). Furthermore, models, such as thermal exergy, thermal network, and bargaining game goal, are linearized. It dramatically reduces the computational cost and can easily be solved by Cplex or Gurobi. Finally, numerical studies with three EHs and one HS demonstrate the effectiveness of the proposed method. In the case study, the overall cost of EH and HS can be reduced by 2.60% through the interaction of electric power, thermal power, and exergy loss. [ABSTRACT FROM AUTHOR]

Applied to the production of windings, the printed circuit board (PCB) technology is promising for developing high performance slotless permanent magnet machines, since it allows for winding shapes and topologies that are difficult to obtain with the classical wire technology. However, compared with wire windings, PCB windings are more prone to eddy current losses because of the high width-to-thickness ratio of the conductor cross-section. To counteract these eddy currents, the conventional solution consists of reducing the width of the conductive tracks constituting the winding in conjunction with an increased number of turns. To keep the supply voltage within limits compatible with the power supply, parallel connections of the tracks at the winding terminals are required. This article tackles the eddy current problem differently by adding some slits distributed along the conductive tracks. This amounts to carry out local parallelizations without impacting the motor supply voltage. By means of parametric analyses carried out on different slit configurations and considering their impact on both the supply and eddy current losses, this study shows that a parallel reconnection of successive tracks two by two gives almost the same results as a classical parallel connection of all the tracks, independently of the winding shape. Furthermore, this article concludes that the optimal number of parallel slits is fixed and valid for a large range of nominal speed-torque ratios. However, it is necessary to increase the width of the slits when this ratio becomes very high and it is technically no longer possible to increase the number of slits. [ABSTRACT FROM AUTHOR]

This article develops a high-power piezoelectric transformer based on the sandwiched piezoelectric transducer with multioutput characteristics. An advanced high-power voltage transformation technology is realized via using the superior mechanical robustness of the sandwiched piezoelectric transducers. High-power sandwiched piezoelectric transformers (s-PTs) with the unique crisscrossed structure are constructed by four sandwiched piezoelectric transducers with two modes, i.e., antiphase mode and in-phase mode, due to the coupled vibration of the central metal cuboid. Moreover, the related electromechanical equivalent circuit model (EECM) of the s-PTs is established in which two loss factors are introduced into this model, and its impedance characteristics, voltage gains, and power gains are studied as well. The accuracy of EECM is verified by the finite element method and experiments. Results reveal that s-PT has three outputs, and its voltage gains and power ratios are affected by load resistance and loss. The output power of the s-PTs can reach at least 45 W, and the s-PTs can keep the efficiency of ∼35% under high-input electric power, which provides a new idea for high-power piezoelectric transformers. [ABSTRACT FROM AUTHOR]

This article proposes a generalized energy storage model for battery energy storage systems, electric water heaters (EWH), and heating, ventilation, and air-conditioning (HVAC) systems to enable demand response control complying to Energy Star and CTA-2045 standards. The demand response control has been implemented in the DER integration testbed, which was originally developed by Electric Power Research Institute, to demonstrate that the “energy content” and “energy take” for BESS and EWH with mixing valve technology are comparable for typical residential ratings. A distribution power system was modeled using the modified IEEE 123-bus feeder system, measured residential loads, and EWH power simulated based on realistic hot water draws from CBECC-Res software. The demand response control, which complies to CTA-2045 standards was implemented to the EWHs considering the energy take values. Results demonstrate that the EWHs can be controlled to postpone the peak power at the distribution system level and provide a large amount of energy storage, while maintaining system robustness. The impact on occupant comfort was also analyzed. [ABSTRACT FROM AUTHOR]

Current research on Deep ReinforcementLearning (DRL) for automated on-ramp merging neglects vehicle powertrain and dynamics. This work considers automated on-ramp merging for a power-split Plug-In Hybrid Electric Vehicle (PHEV), the 2015 Toyota Prius Plug-In, using DRL. The on-ramp merging control and the PHEV energy management are co-optimized such that the DRL policy directly outputs the power split between the engine and the electric motor. The testing results show that DRL can be successfully used for co-optimization, leading to collision-free on-ramp merging. When compared with sequential approaches wherein the upper-level on-ramp merging control and the lower-level PHEV energy management are performed independently and in sequence, we found that co-optimization results in economic but jerky on-ramp merging while sequential approaches may result in collisions due to neglecting powertrain power limit constraints in designing the upper-level on-ramp merging controller. [ABSTRACT FROM AUTHOR]

Safeguarding the nation’s electrical infrastructure and personnel against natural and man-made disasters, and ensuring a continuous, reliable, and resilient supply of energy are among the top priorities for the electric industry. In recent years, wildfires have been remarkably threatening the safety and security of electric power grids demanding innovative frameworks for ensured resilience. Our proposed approach focuses on mitigation of wildfire disruptions that, once occur, can jeopardize the well-being of electrical equipment and the safety of the personnel. The proposed framework first offers a comprehensive wildfire characterization package that can spatiotemporally monitor and analyze the wildfire behaviors, i.e., wildfire intensity, arrival time, and binding paths from ignition points to electrical equipment. This allows power system operators to make proactive decisions before the fire approaches the electrical elements, e.g., power distribution lines. Next, a decision support tool for wildfire management in power grids is proposed such that various local generation resources,—i.e., distributed renewable energy resources and energy storage systems, can be effectively employed to mitigate the wildfire impacts on the power grid. The proposed integrated solution technology ensures a significant reduction in power outages and enhances the safety and resilience of the power grid and the operating personnel. [ABSTRACT FROM AUTHOR]

Vehicle-to-grid (V2G) technology enables bidirectional energy flow between the electric vehicle and power grid thereby making the electric vehicle as a virtual power plant. This seamless exchange of energy flow is possible only when the entities involved communicate wirelessly in a secured manner. In order to ensure privacy-preserving in the V2G communication, development of a novel key establishment protocol is an active area of research. This article presents a lightweight mutual authentication and key establishment protocol for secure V2G communication among the electric vehicle user, charging station, and utility service provider. The correctness of the proposed protocol is verified using the formal method BAN logic, and many of its security threats are analyzed informally. Further, the protocol is compared for its security and efficiency with the related protocols in the literature under various aspects, and the comparison results show that our protocol outshines the others. The functional correctness of the protocol is also verified in Xilinx Zynq-7000 series FPGA board so that it can be deployed in any real-time applications. [ABSTRACT FROM AUTHOR]

Series-connected multipulse rectifiers (MPRs) are used to provide high-quality electric power for high-voltage and high-power occasions. Due to conventional MPRs have limited harmonic reduction ability that cannot fulfill the related harmonic standard, some effective dc side harmonic reduction methods have been proposed to further improve power quality of the MPRs. This article gives a comprehensive review on dc link harmonic reduction methods of series-connected MPRs. Passive and active harmonic reduction mechanisms are respectively analyzed based on two typical topologies, which are theoretical foundations for understanding and constructing novel harmonic reduction circuits (HRCs). Some useful dc side HRCs are presented and compared from aspects of their performances, complexity of the overall structure, magnetic device capacity and power losses, etc. The necessary simulation results are given to verify and compare the effectiveness of some involved harmonic reduction methods. Based on these topologies, the advantages, drawbacks and future trends of the passive or active methods are concluded; besides, the hybrid harmonic reduction methods are also considered. This article aims to provide useful guidance for the researches of harmonic elimination and multipulse rectification technology. [ABSTRACT FROM AUTHOR]

In recent years, the idea of green aviation and environmental protection has received increasing attention from the aviation industry. Hydrogen energy has an important role in the transition to low-carbon energy systems. To address that, this article conducts the technoeconomic analysis for the hydrogen energy system, photovoltaic energy, battery storage system, electric auxiliary power unit (APU) of aircraft, and electric vehicles (EVs) into the electrified airport energy system. Specifically, the model quantifies aircraft electrical load based on passenger’ travel behavior, establishes a corresponding APU load characteristic model, and establishes an EV charging load profile based on the flight schedule and sequencing algorithm. A mixed-integer linear programming optimization method based on life cycle theory was proposed to minimize the total costs of hydrogen-integrated energy systems for airports (HIES). However, the resilience advantages of hydrogen energy concerning power failure are little explored in existing academic research. Thus, a resilience assessment method and improvement measure were proposed for HIES. Case studies have been conducted under different optimal hydrogen energy integration configurations and disaster times with resilience assessment by considering periods when the power supply capacity of the grid is insufficient. The results show the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Hydrogen has shown great potential in the renewable power integration and urban mobility decarbonization like hydrogen fuel cell vehicles (HFCVs). The HFCV refueling as an essential hydrogen load is of great flexibility. Considering the HFCV demand response (DR), this article studies the integrated electric power and hydrogen system (IPHS) operation. First, the HFCV refueling load model is formulated with its routing on the transportation network considered. Second, the optimal IPHS operation model is developed in which the electric power operation, tube-trailer based hydrogen delivery and HFCV refueling are coordinated. Third, a Lagrangian relaxation based method is developed to solve the proposed model efficiently, which corresponds to a price-based DR mechanism for HFCVs. Compared with existing works on IPHS, the influence of transportation networks is delicately analyzed on both HFCV refueling and hydrogen delivery. The case studies have proven the effectiveness of the proposed method and demonstrated that the overall operation cost is decreased via the proper guidance of HFCV refueling. The HFCV DR shows great potential in exploring the synergy of energy and transportation systems. [ABSTRACT FROM AUTHOR]

In this article, we demonstrate a flexible and wearable hybrid radio frequency (RF) and solar energy harvesting system for powering wearable electronic devices. The system consists of a flexible transparent antenna, a flexible transparent rectifying circuit, and an amorphous silicon solar cell. By utilizing transparent stacked structure, the rectenna and the solar cell can provide more hybrid output power to accommodate more application scenarios. The flexible transparent antenna shows two impedance matching bandwidths of 3.5–3.578 and 4.79–5.09 GHz, covering n78/n79 fifth-generation (5G) communication frequency band and 5-GHz WiFi frequency band. At the frequency of 3.5 GHz, the flexible transparent rectifying circuit achieves a high RF-to-dc conversion efficiency of 54.67% at 13 dBm RF input power. In the room with a light intensity of 210 lux, compared with a single solar cell, the hybrid energy harvesting system can obtain an additional 35.6%–769.5% output power when the RF source power is varied from 4 to 10 dBm. These results demonstrate that the proposed flexible and wearable RF-solar energy harvester can provide reliable electric power supply, which can be a potential candidate for powering wearable electronic devices, distributed sensors and IOT devices. [ABSTRACT FROM AUTHOR]

Batteryless energy-harvesting devices promise to deliver a sustainable Internet of Things. Intermittent computing is an emerging area, where the application forward progress, i.e., computation beneficial to the progress of the active application, is maintained by saving the volatile computing state into nonvolatile memory before power interruptions, and restored afterward. Conventional intermittent computing approaches typically minimize energy storage to reduce device dimensions and interruption periods, but this can result in high state-saving and -restoring overheads and impede forward progress. In this article, we argue that adding a small amount of energy storage can significantly improve the forward progress. We develop an intermittent computing model that accurately estimates the forward progress, with an experimentally validated mean error of 0.5%. Using this model, we show that sizing energy storage can improve the forward progress by up to 65% with a constant current supply, and 43% with real-world photovoltaic sources. An extension to this approach, which uses a cost function to trade off the energy storage size against forward progress, can save 83% of capacitor volume and 91% of interruption periods while maintaining 93% of the maximum forward progress. [ABSTRACT FROM AUTHOR]

The history of the use of electricity in Japan began as telecommunication, which started in 1869, one year after the Meiji Restoration. The first electric arc lamp shone in Ginza, Tokyo, in 1882, the same year as the start of operation of Edison's Pearl Street Power Plant in New York. Only four years later (1886), Tokyo Electric Light Company, one of the predecessors of Tokyo Electric Power Company Holdings, started its business as the first electric power company in Japan. Many similar companies started their businesses in the following several years. In these early days, electric power companies in eastern Japan imported 50-Hz generators from Allgemeine Elektricitäts-Gesellschaft (AEG) in Germany, and those in western Japan imported 60-Hz generators from General Electric Company in the United States. From this historical background, AC 50 Hz is still used in eastern Japan and 60 Hz in western Japan. [ABSTRACT FROM AUTHOR]

Wireless power transfer (WPT) is emerging as the preeminent way to charge electric vehicles, but there appears to be no fair way to measure the power transfer. In this article, Faraday coil transfer-power measurement (FC-TPM) is presented. FC-TPM employs non-contact, open-circuited sense coils to measure the electromagnetic field from WPT and calculates the real power propagating through the air gap between the transmitter and receiver coils. What is measured is the real electromagnetic power, representing the pure dispensation of energy that unambiguously demarcates the losses on either side. FC-TPM was demonstrated to be 0.1% accurate in hardware over an Rx coil misalignment of up to 10 cm using a 1-kW WPT system. Fair metering incentivizes businesses and individuals to make choices that conserve energy and advance technology by providing more information and by properly assigning the financial loss. This article is accompanied by a video highlighting the essential contributions of this article. [ABSTRACT FROM AUTHOR]

For installation in the public electric power grid of the city of Augsburg, Germany, a resistive superconducting fault current limiter (SFCL) was designed, constructed, tested and operated in the framework of a partially funded project ‘ASSiST’. Right from the beginning, it was agreed to aim for a prolonged operation even after closure of the project. This endeavor has been started due to a fundamental need to limit the prospective fault currents at a feeder point of the grid and in order to create long-term operational experience on a device seamlessly integrated into commercial grid components and switchgear, thus demonstrating a high level of readiness for widespread application. It revealed that the SFCL was of robust design – withstanding all electrical tests including a special two-phase fault and sustaining stable cryogenic conditions even during partial outages of the cooling system – and that the technology is reducing loss by shunt reactors. Furthermore, due to the control equipment on medium voltage level, valuable insights on grid behavior could be gained. The extended operation for 4 years has clearly shown the performance and robustness of SFCL technology in feeder points on MV level and provides a reference point for further commercialization. [ABSTRACT FROM AUTHOR]

For fault ride-through requirement, solar photovoltaic (PV) plant remains connected to the grid during a fault. In such a situation, a PV plant operates in different modes and supplies current to comply with the requirements of the grid. The relative magnitude of phase current contributed by a PV plant during a fault is at par with the nominal current. Such a fault behavior restricts the application of available phase current based relaying approaches while protecting the distribution system with a PV plant. A protection method using local positive sequence voltage and current is proposed to protect a distribution system with PV plant. The method selects pickup current using proposed current-voltage curve for fault detection. A three-dimensional time-current-voltage characteristic is proposed for trip time calculation. Performance of the proposed method is tested for relays on both PV plant side and grid end using DigSilent PowerFactory simulation data for a CIGRE 14-bus distribution system with PV plant having different modes of operations. The method is found to be accurate and comparative assessment reveals its superiority. [ABSTRACT FROM AUTHOR]

For a broad range of industrial, service, and household electric vehicles, dynamic charging is a viable option for energy replenishing that could reduce the size of the onboard energy storage, remove range limitations, and increase operating time. For these systems, timely detection of an approaching vehicle and the detection of strong coupling conditions between transmitter and receiver coils are of prime interest. A novel method is proposed in this article, which utilizes the existing embedded transmitter coil and power electronics modules to establish a precise detection system based on the power footprint of a traveling receiver. Next, a control algorithm is proposed to control charger activation and deactivation time accurately and deliver the required energy during the maximum coupling of the coils. The proposed sigmoid-curve-based control algorithm achieves a robust, speed-independent, smooth transition between two states while providing fast dynamics for aligned and misaligned conditions. Finally, a novel approach to test high-speed dynamic charging in laboratory conditions based on the receiver emulator is developed and used for experimental validation. The vehicle detection and control techniques have been validated through simulations and experimentally on a speed-controlled dynamic charging test station for a wide speed range. The proposed method does not require any additional hardware, sensing devices, or high-speed communication between the vehicle and the charging infrastructure. [ABSTRACT FROM AUTHOR]

For fast buffering of large stepwise input to an nF-range capacitive load, this article presents a 5-V rail-to-rail (RTR) input–output paralleled-amplifier (PA) in which a dynamic class-C amplifier (DCCA) and a linear single-stage operational transconductance amplifier (OTA) are combined in parallel. During slew time, the DCCA, which is designed to consume a near-zero static current, dominantly supplies the dynamic current up to 8.5 mA to the output. When the output gets closer to the fine-settling region, the DCCA is rapidly faded out in virtue of a dedicated near-zero dead-zone control (NDZC), and it hands over to the linear OTA. A current-redistributive RTR $G_{\text {m}}$ -boosting technique is also proposed so that the OTA can have a wide gain-bandwidth product (GBW) even over the RTR input range while minimizing the quiescent current dissipation. The prototype chip was fabricated only with 0.5- $\mu \text{m}$ 5-V CMOS devices, and it occupies a die area of 0.03 $\mu \text{m}^{2}$. The proposed amplifier consumed a static current of 3.1 $\mu \text{A}$ with a supply voltage of 5 V. The slew rates (SRs) with load capacitances ($C_{\mathrm {L}}$) of 0.8 and 10 nF were measured to be 10.3 and 0.86 V/ $\mu \text{s}$ , respectively, for a step input of $\Delta $ 4.2 V, which is a state-of-the-art result compared to prior chips. The measured GBW of 10–127 kHz was achieved over 0.8–10 nF $C_{\mathrm {L}}$ with ≥ 59° phase margin (PM). The measured GBW deviation in a common-mode voltage ($V_{\mathrm {CM}}$) range of 0.3–4.7 V was within the maximum of 20%. [ABSTRACT FROM AUTHOR]

Welcome to a Special Issue of the IEEE Canadian Journal of Electrical and Computer Engineering (ICJECE), which presents some of the top articles (in extended form) from the Electric Power and Energy Conference (EPEC 2020) held on November 9–12, 2020. The theme was “Power Systems in Transition.” This conference was originally planned to take place at the University of Alberta, Edmonton, AB, Canada, but the COVID-19 global pandemic required pivoting to a virtual (online) platform. This marks the first time this conference was held remotely. EPEC 2020 was hosted by the Northern Canada Section, with five cosponsors (IEEE Canada, IEEE Southern Alberta Section, IEEE North Saskatchewan Section, IEEE Winnipeg Section, and the IEEE IAS/PES Northern Canada Chapter) and two technical cosponsors (IEEE PES and IEEE PELS). [ABSTRACT FROM AUTHOR]

The problem of frequency tuning a cantilever piezoharvester to the typical vibrations of a bicycle is here investigated. This is a key to optimize the energy harvesting performance. Road tests with a bicycle on a typical city track are first carried out to measure the power spectral density of bike vibrations. Both analytical and experimental methods are used to estimate the average electric power that can be harvested by a piezoharvester with a solid tip mass. This solution is compared with a tuning strategy based on a liquid tip mass by using a novel analytical method for simulating frequency response. [ABSTRACT FROM AUTHOR]

This work presents a wide-range, submicrowatt CMOS rectifier, which is designed to efficiently work at input power levels down to −31 dBm. The designed rectifier uses a novel threshold voltage compensation design, namely, the design of a custom-built single-stage rectifier that supplies a nanowatt current reference circuit. The generated bias current is mirrored to the core rectifier in order to precharge its CMOS diodes. The rectifier was optimized for a minimum number of gain stages while trying to minimize the overall input parasitic capacitance of the rectifier. The proposed CMOS rectifier was designed in an in-house 130-nm CMOS technology and includes a 1.6-kV human body level ESD protection at the input terminals. Measurements reveal a high 30% power conversion efficiency (PCE) over a wide input power range from −23 to −13 dBm for a 1- ${\mathrm{ M}}\Omega $ output load at 868 MHz. PCE of over 10% is achieved for a 1- ${\mathrm{ M}}\Omega $ load at an input power of −28 dBm. The enhanced startup at submicrowatt input power levels of the CMOS rectifier enables the design of an ultralow-power passive wake-up receiver. The measured sensitivity of −31 dBm for a 1-V output voltage across a capacitive load is the lowest reported in the literature so far. [ABSTRACT FROM AUTHOR]

This article presents an investigation on the optimal design of a transmit coil for a wireless power transfer system (WPTS) for biomedical implants with the goal of maximizing the magnetic flux density (B-field) at the location of the implant while not violating magnetic field exposure limits. Maximizing the B-field correlates to higher transferable electric power for certain WPTSs, such as those that use magnetoelectric receivers. While previous works have optimized the thermal efficiency, or system efficiency, to our knowledge no one yet has developed the procedure to optimize the transmitter to maximize the B-field subject to an imposed safety limit constraint for magnetic field exposure. In addition to this safety constraint, the optimal design of the transmitter is considered when the system geometry or the input current is constrained. Equations for determining the design parameters of an optimal solenoid transmitter are derived subject to constraints on either transmitter size or electric current. If a certain magnetic field strength is required, solutions to the size and current of the transmitter are presented, which allow the desired fields without violating the safety constraint. The mathematical model is experimentally validated, and a case study is described that illustrates the optimal design rules. [ABSTRACT FROM AUTHOR]

A single-phase symmetric-bipolar-type high-frequency isolated buck-boost ac–ac (SBT-HFI-BBAC) converter is proposed. The converter is composed of two full-bridge inverter modules, input/output LC filters, and a high-frequency transformer (HFT) with series capacitors. It can provide identical noninverting and inverting buck-boost output voltages with symmetric-bipolar voltage gains of $ \pm D/({1 - D})$. The frequency of the output voltage can also be adjusted in discrete steps, similar to single-phase matrix converters (MCs). It supplies continuous input and output currents and works well with nonunity power factor loads. The magnetizing current of the HFT has no line frequency component due to the presence of the series blocking capacitors. Moreover, due to the absence of ac switches, the converter has a simple commutation process, unlike conventional ac-ac/MCs. Two switching strategies are proposed; Strategy-I with fewer high-frequency switches and Strategy-II with reduced switch currents, providing more flexibility in switch power loss optimization. The proposed SBT-HFI-BBAC converter is well suited for application as a dynamic voltage restorer, compensating a wide range of grid voltage sags and swells, without the need for a low-frequency voltage injection transformer. Its step-changed frequency operation can also find use in various applications, such as high-gain ac–dc converters, traction systems, etc. A comprehensive description of circuit operation is presented along with component design guidelines and appropriate comparisons. Experimental verification results are provided using a 400-W laboratory test circuit. [ABSTRACT FROM AUTHOR]

The Technology development and rising standards of living are increasing the demand for electricity in city centres. In addition, the density of electric power in different areas of a city changes with the construction of new residential areas. Variation in load density can be managed by adjusting the voltage on distribution lines, installing new lines and transformer centres, and reconfiguring existing lines and transformer centres. In this study, the Istanbul Uskudar District of Kanlica-Cubuklu Region was examined and coverage areas were modified depending on the load density and power of the existing transformers. A novel systematic approach to determine the coverage area of transformers is presented. In this approach, the coverage area and overlap of each transformer with its neighbours were determined. Subsequently, transformers that are under-used or have significant overlap with neighbouring transformers were removed from the network. The transformers were placed into an optimal structure in the network by distributing the load of an excluded transformer to its nearest neighbours. This approach further allows the minimum route for the high voltage distribution wiring between transformers and cost to be determined. [ABSTRACT FROM AUTHOR]

In this article, a new nonisolated interleaved dc–dc converter with extremely extended duty cycle and low current ripple is presented. The applied interleaved architecture along with complementary operation of the switches provide zero voltage switching condition for all switches and reduce the output current ripple. Both of diodes turn ON and turn OFF under zero current switching condition, and thus the reverse recovery losses associated with the diodes are eliminated. In the proposed converter, energy-transferring capacitors are used as voltage sources to reduce the input voltage and the switches voltage stress. Also, the coupled inductors are applied to extend the duty cycle while the leakage energy is absorbed without imposing extra voltage stress across the switches. As a result, extremely high step down voltage conversion ratio is achieved and the overall efficiency is improved. In this architecture, the input shares the ground with the output and any auxiliary circuit is not required. The operating modes of the proposed converter are analyzed and the presented experimental results confirm the theoretical analysis. [ABSTRACT FROM AUTHOR]