The wireless power transfer (WPT) coils are built with litz wires to minimize the skin effect and eddy loss. Precise modeling of litz wires leads to enormous meshes and takes lengthy simulation time in finite element analysis (FEA). Various equivalent analytical models often use solid conductors with uniform current distribution to realize litz wires, which fail to include the twisting and stranding effect. Also, for mutual inductance calculation, various geometrical over-simplifications are made to reduce the complexity of the analytical model. These simplifications add significant errors in the self and mutual inductance parameter estimation. This paper proposes improved analytical modeling for the litz wire-based rectangular planar spiral coils with a ferrite core for precise parameter calculation. The proposed modeling method also addresses lateral misalignment between WPT coils. The accuracy of the proposed modeling is compared with existing modeling methods, FEA simulation, and experimental results obtained from the rectangular spiral coil hardware prototypes. The proposed model is 5 to 6 times more accurate than the existing solid conductor analytical method.

Two-level rectifiers are commonly utilized in electrical systems, particularly for low power ratings, owing to their inherent limitations at medium and high power levels. Operating at medium and high power ratings presents challenges, such as the need for high-rated switches, increased total harmonic distortion (THD), and increased costs. In this paper, a three-level T-type neutral point clamped (TNPC) rectifier is modeled and analyzed for medium power rating. Circuit description, mathematical modeling, and proportional-integral (PI) based controllers are implemented to control grid current and DC-link voltage dynamics effectively, thereby ensuring efficient active power transfer to the load. Additionally, MATLAB simulations are conducted for a power rating of 80 kW. Furthermore, the performance of the converter is validated through controller hardware-in-loop (C-HIL) using the advanced Typhoon HIL 402 platform. The results, including lower THD in grid current and unity power factor at the grid side, highlight the effectiveness of the control strategy for the TNPC rectifier.

This paper focuses on the closed-loop control of a three-level bidirectional DC-DC converter (TL-BDC), specifically designed for charging and discharging batteries in various applications involving electric vehicles (EVs), renewable energy systems (RES), and uninterruptible power supplies (UPS). This research shows a comprehensive study, commencing with state space analysis to grasp the details of the system dynamics. Subsequently, The study moves on to the simulations of TL-BDC using MATLAB Simulink. In this phase, proportional-integral (PI) control mechanisms manage the converter’s operations. Also, simulation results for the parallel operation of TL-BDC are presented. Moreover, controller hardware-in-loop (C-HIL) simulations are performed using the advanced Typhoon HIL 402 platform to validate the efficacy and real-world applicability of the proposed control strategies.

This work aims to design and develop a contactless magnetic plug for convenient and safe charging of electric vehicle batteries. This is achieved by introducing an insulation gap in the high-frequency transformer located between the DC-AC and AC-DC power conversion stages. The gap in the transformer core and windings constitute a detachable plug that is contactless, electrically safe, very convenient, and eliminates any possibility of arcing and aging of contact. The design parameters of the magnetic plug are derived analytically and then verified using COMSOL. Two different closed-loop control techniques have been discussed to regulate the output voltage. A 5 kW 400V DC input and 96V DC output charging circuit are analyzed, designed, and simulated in PowerSIM. A scaled-down lab prototype of 1.0 kW is developed to convert power from 240V DC input to 60V DC output. The experimental results obtained from the lab prototype verify the proposed converter design. Several dynamic response results are also included to show the performance of the closed-loop system. The proposed design can be scaled up easily to higher power levels for fast charging.

This paper presents a numerical analysis and performance comparison of different modulation techniques for a specific power range on the Series Resonant Dual Active Bridge (SR-DAB). The SR-DAB is a widely used dc-dc converter with a bi-directional power flow. The modulation techniques predominantly affect the performance and efficiency of SR-DAB. Thus, analysis and comparison of modulation techniques, such as Single Phase Shift (SPS), Extended Phase Shift (EPS), and Dual Phase Shift (DPS), are performed on SR-DAB. A Modified Pulse Width Modulation (M-PWM) technique with optimal control is proposed to enhance performance, such as extended soft switching and reduced reactive power circulation. Control based on Minimum Current Trajectory (MCT) is implemented to optimize and achieve maximum efficiency of the M-PWM technique with SR-DAB. The numerical analysis and comparison are verified using simulation results, and a prototype of 500W is built for experimental verification of the M-PWM with the MCT technique.

The phenomenon of compounding is ubiquitous in Sanskrit. It serves for achieving brevity in expressing thoughts, while simultaneously enriching the lexical and structural formation of the language. In this work, we focus on the Sanskrit Compound Type Identification (SaCTI) task, where we consider the problem of identifying semantic relations between the components of a compound word. Earlier approaches solely rely on the lexical information obtained from the components and ignore the most crucial contextual and syntactic information useful for SaCTI. However, the SaCTI task is challenging primarily due to the implicitly encoded context-sensitive semantic relation between the compound components. Thus, we propose a novel multi-task learning architecture which incorporates the contextual information and enriches the complementary syntactic information using morphological tagging and dependency parsing as two auxiliary tasks. Experiments on the benchmark datasets for SaCTI show 6.1 points (Accuracy) and 7.7 points (F1-score) absolute gain compared to the state-of-the-art system. Further, our multi-lingual experiments demonstrate the efficacy of the proposed architecture in English and Marathi languages.

Gallium nitride (GaN) based power devices are promising technology for power electronic circuits to achieve high operating frequency, low conduction loss, and zero reverse recovery loss. However, these devices suffer from the dynamic on-resistance (R ds, on ) in the application. To investigate this issue, several test circuits are discussed in the literature. In this paper, a summary and their limitation on testing parameters during R ds, on evaluation are discussed. The test circuits are further analyzed based on their switching stress to the device under test (DUT). This analysis may provide insight for test engineers to choose the test circuit based on their requirements quickly, and researchers interested in this topic will have the state-of-the-art circuits from this paper.

At present, the field of power factor corrected (PFC) rectifiers are very much matured. Typically a single phase PFC converter requires measurements from three independent sensors i.e. input voltage, input current and output voltage. By considering a need of farther compact and more flexible in terms of input to output voltage gain, a new UPF rectifier with two buck-boost converter operating in interleaved condition with use of only one output voltage sensor is presented. The proposed control technique uses only integrator to compensate the error between measured voltage and reference voltage and it is very simple to implement. The proposed Buck-boost converter operates in Discontinuous Conduction Mode (DCM) to achieve UPF at AC input. The required buck-boost inductance in DCM operation is quite small. In contrast to this, the current ripple of buck-boost inductor is quite high. Interleaving is the viable option to reduce the inductor current ripple, component stress, input filter size and enhances the power density. To verify the feasibility of the proposed scheme, the proposed converter is repeatedly simulated in PSIM and in real time platform OP4510. A scaled down lab prototype is built and experimental results are presented to verify the suitability of the proposed converter for the practical application.