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The present work describes a control methodology for a hybrid energy storage system (HESS) to improve its transient performance under dynamic load conditions. The proposed coordination control enhanced life cycle performance by segregating the power between battery energy storage systems (BESS) and a supercapacitor (SC). The BESS and SC are connected parallel to each other, and two individual DC–DC bidirectional converters connect them to a common DC bus. The coordination control is established between the controllers of BESS and the SC of HESS, which helps to utilise the usable energy capacity of the HESS. The charging/discharging current of the BESS is controlled within the allowable safety range based on the slope and magnitude of the BESS current. The high-frequency power component is handled by the SC, which helps to reduce the extra exhaustion on the BESS during operation with a higher current. The proposed coordination control of HESS is validated through simulation and the results show the effectiveness of the proposed controller.

This paper proposes an improved space vector pulse width modulation (SVPWM) based DC link voltage balancing control of a three-phase three-level neutral point clamped (NPC) centralised inverter supplying the generated power from photo voltaic (PV) array to a three-phase utility grid. Two possible schemes have been developed based on the power conversion stage between PV array and the utility grid namely, two-stage (three-level boost converter three-phase three-level NPC inverter) and single-stage (three-phase three-level NPC inverter alone). The comparison between these two schemes has been thoroughly discussed in terms of the control strategies employed, power loss analysis and efficiency. The performance of the centralised inverter under different modes of operation has been investigated by developing the required control strategies for smooth operation. Using the proposed control strategy, the centralised inverter can be operated as a static synchronous compensator (STATCOM) during night time, if needed. The power loss incurred in the power-electronic converters has been analysed for constant and also for variable ambient temperature. The effectiveness of the centralised inverter as an active filter (AF) has also been verified when a three-phase non-linear load is considered in the system.

The increase in renewable power injection into the existing ac network has affected voltage and frequency stability. This creates the need for both active and reactive power support systems at the Common Coupling Point (CCP) of a renewable power generating station. Considering the aforesaid requirements, a distinct configuration using a Modular Multilevel Converter (MMC) with Hybrid Storage System (HSS) has been recommended in this paper. These kinds of systems are termed as "Statcom Embedded with Storage System"(SESS). The SESS helps to pump invariable power into the grid by absorbing fluctuating components of active power generated by the renewable power generating plant. Apart from this, provides ancillary services at CCP like, voltage regulation and compensation for negative sequence currents, and ride through capability during the faults in the ac system are to be provided by SESS. The required control methods to operate the proposed configuration for the aforesaid necessities are discussed in this manuscript. The economic advantage of the proposed configuration in comparison to other multilevel topologies has been identified using a techno-economic study and it is presented. The competency of the recommended configuration for SESS application along with its control is verified through PSCAD/EMTDC simulation and the results show its efficacy. [ABSTRACT FROM AUTHOR]

In this paper, a detailed study on the Model Reference Adaptive Controller (MRAC) utilizing the reactive power is presented for the online estimation of rotor resistance to maintain proper flux orientation in an Indirect Vector Controlled Induction Motor Drive. Selection of reactive power as the functional candidate in the MRAC automatically makes the system immune to the variation of stator resistance. Moreover, the unique formation of the MRAC with the instantaneous and steady-state reactive power completely eliminates the requirement of any flux estimation in the process of computation. Thus, the method is less sensitive to integrator-related problems like drift and saturation (requiring no integration). This also makes the estimation at or near zero speed quite accurate. Adding flux estimators to the MRAC, a speed sensorless scheme is developed. Simulation and experimental results have been presented to confirm the effectiveness of the technique. Index Terms--Drift and saturation, indirect vector control, model reference adaptive controller (MRAC), reactive power.

Introduction: Estimation and evaluation of growth of children undergoing orthodontic treatment is of great importance. Body mass index percentile offer quick, non-invasive estimation of development status whereas onset of menarche is an important biologic indicator in assessing the physiologic maturity in girls. Assessment of skeletal maturity with hand-wrist radiograph is also reliable, predictable and popular method. Aim: To correlate between body mass index percentile, age at menarche with hand wrist radiograph in female population. Materials and Methods: This cross-sectional study was conducted at Guru Nanak Institute of Dental Sciences and Research, Kolkata, West Bengal, India, from May 2022 to March 2024 with study population of 100 Bengali girl between 9-15 years age whose origin within six months of onset of menarche were selected. BMI was measured individually, and Hand-wrist X-ray was taken for assessment of skeletal age of every individual. The collected data was tabulated using Microsoft Excel 2019 and then statistical analysis was carried out using the GraphPad Prism for Windows, Version 9.5. Results: Mean age of the study subjects was found to be 12.41±1.41 years, mean BMI was found to be 18.62±2.7 kg/m². Majority of the study subjects were found to be healthy (66%) at stage VIII of skeletal maturity. Conclusion: Obese girls had the onset of menarche at an early stage followed by Overweight girls then Normal weight girls whilst the underweight girls had their late menarche. The correlation between SMI method and the onset of menarche was statistically insignificant but significant correlation was found between BMI percentile and SMI staging method. [ABSTRACT FROM AUTHOR]

In this article, the Gershgorin disk theorem in complex interval matrices is proposed for enclosing interval eigenvalues. This is a non-iterative method for finding eigenvalue bounds for both real and imaginary parts. Moreover, we are able to find gaps between the clusters of interval eigenvalues and have compared the results with the previous theorems for interval eigenvalue bounds for complex interval matrices. These results can be decisive for checking Hurwitz and Schur stability of complex interval matrices that appear in uncertain dynamical systems. Further bounds obtained from the present formulae can be considered as the initial bounds for iterative methods. [ABSTRACT FROM AUTHOR]