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Managing the high‐rate‐power transients of Electric Vehicles (EVs) in a drive cycle is of great importance from the battery health and drive range aspects. This can be achieved by high power‐density storage, such as a high‐speed Flywheel Energy Storage System (FESS). It is shown that a variable‐mass flywheel can effectively utilise the FESS useable capacity in most transients close to optimal. Novel variable capacities FESS is proposed by introducing Dual‐Inertia FESS (DIFESS) for EVs. The feasibility of the proposed concept is evaluated by deriving the size of a Single‐Inertia FESS (SIFESS) for a battery EV, which runs the well‐known Urban Dynamometer Driving Schedule. The sizing framework consists of an Energy Management System using the constrained Pontryagin's minimum principle and a proposed sizing algorithm. Then, by splitting the derived SIFESS inertia into two separate inertias, the appropriate engaging control of inertias is determined for some driving cycles including, the Artemis Urban, Braunschweig City, and Worldwide Harmonised Light‐duty Vehicles Test Cycle. The dual inertias suitable sizes are derived using a proposed algorithm, which targets maximising the FESS useable capacity. The results show that compared to the SIFESS, the DIFESS can employ the FESS's useable capacity more effectively. [ABSTRACT FROM AUTHOR]

The grid‐connected photovoltaic plants (GCPVPs) encounter various types of anomalies during fault occurrence in the main grid. During a fault occurrence on the grid side, the voltage of the point of common coupling (PCC) drops, causing the DC connection voltage to become too high for power balancing. This high DC voltage may damage the inverter and DC link equipment, which necessitates a reliable control scheme with low voltage passage requirements. These requirements, which obligate the GCPVP to remain connected to the main grid during abnormal conditions are generally known as low voltage ride‐through (LVRT). Herein, a developed LVRT method in the control approach that injects maximum rated current during a sag is proposed to rectify the shortcomings in single and multi‐inverter grid topologies. The proposed approach utilizes a current limiter combined with a DC braking chopper to guarantee the GCPVP's continuous participation in the power supply. Different scenarios including low and high power generations as well as two‐phase and three‐phase severe faults to the ground are considered. The results show that the proposed approach not only improves the performance in the single‐inverter system but also remedies the defects aggravated in the case of a GCPVP with several inverters. [ABSTRACT FROM AUTHOR]

An efficient method for the detection of the stator winding faults (SWFs) of induction motors was dealt based on Park's vector of rotor slot harmonics (RSHs). The induced harmonic voltages of the RSHs in the stator windings are the supreme signatures for fault detection, which can be monitored in the motor currents. Using such a signature, unbalanced supply voltage and stator windings fault situations could be segregated straightforwardly. On the other hand, despite some merits, Park's vector analysis‐based methods suffer from low sensitivity and unreliability in the case of low‐severity faults. To have the advantages of both methods while tackling the shortcomings, Park's vector approach and the RSH signatures are combined in the proposed method. The RSHs are extracted using the fast Fourier transform method and the least squared approach is employed for pattern recognition. Different experimental results under various scenarios, even in the case of low severity faults, confirm that the locus of Park's vector is an elliptical shape in SWFs, while it is shapeless in other cases, such as healthy and unbalanced supply voltage cases. [ABSTRACT FROM AUTHOR]

This study proposes an approach for finding the optimal size of a high‐speed flywheel in an energy storage system based on battery‐flywheel cooperation, called battery‐flywheel energy storage system (BFESS), supplying an electric vehicle. Considering an energy‐based model for the flywheel and battery, including the losses, the optimal control theory is utilised as a two‐dimensional Pontryagin's minimum principle for solving the problem. The objective function of the flywheel sizing problem includes two terms, in which its maximum interaction with the system from the energy and filtering aspects are taken into consideration by a desirable weighting. While energy interaction is a common task, filtering the fast dynamics of the system such as the harsh conditions for the battery is the key role of the considered lightweight and high‐speed flywheel. A trade‐off between the energy contribution and filtering is made, targetted for the long‐term and short‐term dynamics in the drive cycles, respectively. The proposed methodology is presented in detail using some simple dynamics. Also, the sizing is carried out for the ECE‐15 urban drive cycle, the WLTC class‐3 and FTP‐75 drive cycles. The results confirm that by using the determined optimal size of the flywheel energy storage system (FESS), most of the dynamics could be handled from the filtering and energy interaction aspects. [ABSTRACT FROM AUTHOR]

High‐level voltage and extremely low current are the main characteristics of Triboelectric Nanogenerators (TENGs). Despite TENGs, their Integrated Energy Storage (IES) units like supercapacitors and battery units require low‐level voltage and a high amount of current for self‐charging power applications. Using proper materials with higher triboelectric charge density is the most common approach to enhance the output current of TENGs. However, this approach alone does not satisfy the requirement of the integrated energy storage units, in which a relatively low voltage along with a sufficiently high current is needed. Consequently, alternative approaches such as employing a power management circuitry have been proposed. This paper introduces a technique based on the texture of multiple TENGs with identical small surface areas to adapt the TENGs to their IESs, specifically tailored for wearable electronics. Some experiments are conducted to evaluate the merits and limitations of the proposed approach. The experimental and analytical results are thoroughly analyzed to show the capabilities and restrictions of the method. [ABSTRACT FROM AUTHOR]