Current Overshoot Research Articles

Optimization Method of SiC MOSFET Switching Trajectory Based on Variable Current Drive

Silicon carbide (SiC) MOSFETs exhibit superior performance compared to traditional silicon (Si) MOSFETs, characterized by faster switching speeds, lower on-resistance, higher breakdown voltage, and greater operational temperature tolerance. These attributes make SiC MOSFETs highly suitable for applications in electric vehicles, charging stations, and mobile devices. However, their rapid switching speed can intensify current and voltage overshoot and oscillations during device switching, leading to increased device losses or potential damage. To address this issue, this paper proposes a current-type active gate drive (AGD) circuit. The circuit first detects the rate of change in the drain current and drain-source voltage. Subsequently, it employs an analog amplifier circuit and adjustable drive resistors to decelerate the rate of change in the drain-source voltage and drain current. As a result, overshoot and oscillation in the drain-source voltage and drain current are mitigated. Experimental results demonstrate that the proposed AGD circuit can reduce drain current overshoot by 60%, drain-source voltage overshoot by 15.38%, and waveform oscillations. Additionally, the AGD circuit decreases conduction and turn-off losses by 24% and effectively mitigates electromagnetic interference (EMI) issues within the frequency range of 0.1 to 3 MHz.

Advanced control of split source inverter through finite control-set model predictive control for improved system performance.

Distributed power generation systems may necessitate connecting multiple independent energy sources that employ various converter topologies. A recent development in this field is the emergence of impedance source converters, offering the ability to deliver buck-boost functionality within a single stage. The split-source inverter (SSI) has been introduced as a novel choice in between this family. Many control strategies have emerged for electrical power systems control. Among the recent emerging controllers, model predictive control strategies have become an effective technique for control systems. Model predictive controllers (MPCs) offer a number of features compared to the conventional and counterpart models such as enhanced system response and improved system transients with reduced steady-state error. This research suggests a finite control-set MPC for three-phase single-stage SSI supporting a standalone load for remote area applications. Considering the proposed FCS-MPC, the output load current tracks its reference magnitude with minimized error. In addition, the proposed FCS-MPC enhances the proposed SSI system performance with a settling time of 10 μs, and approximately without overshoot in the output current. The system has been validated using Opal-RT OP-4510 and the power loss model of the inverter has been explained. In the end two comparisons have been presented to clarify the main points in the topology structure and the control technique.

Fast Start-Up Control of Both-Side Current Without Overshoot Focusing on Rectification Timing for Dynamic Wireless Power Transfer Systems

The paper proposes a method to improve the tran- sient characteristics of current overshoot and oscillation at the start of power transmission for a dynamic wireless power transfer system. The system is important to reduce the settling time as short as possible without current overshoots for a stable power supply. However, conventional methods to suppress current overshoot have a slow response on the secondary side. This paper proposes the superposition of primary and secondary responses. The proposed method controls the secondary voltage by comparing the steady-state current with the current value on the secondary side. The method can effectively suppress the oscillations in the transient response by applying the secondary voltage at the appropriate timing. This paper also studied the ro- bustness of constraints based on model analysis and experimental verification. In the experiments, the proposed method reduces the current overshoot and the settling time of the secondary current, and maximizes the receiving energy.

Uniformity Improvement of Ti/ZrO2/Pt RRAM by Analyzing and Reducing Current Overshoot

Uniformity Improvement of Ti/ZrO₂/Pt RRAM by Analyzing and Reducing Current Overshoot

Charging delay elimination of solder impregnated HTS coils with specific excitation current

No-insulation (NI) coil has been recognized as the most practical solution at present to achieve ultra-high magnetic field with the REBCO high temperature superconductor thanks to its passive quench protection mechanism which is originated from the inter-turn current bypass. However, for the NI technique, one of the most important obstacles to a more general application is the field delay which is also a consequence of the lack of inter-turn insulation. The proportional and integral (PI) active feedback control of power supply has been developed to achieve a designed field ramping rate. The efficiency of this method could however be affected by the measurement accuracy of measuring equipment, sampling frequency, control accuracy of power supply and other factors. In this manuscript, we tried to use a more fundamental method to mitigate the field delay. The point is, though unlike in insulated coils the field generated is not proportional to coil current in NI coils, they do have a certain linear relation for a certain coil. Based on the lumped circuit model, the current charging curve corresponding to a desired field excitation could be calculated for a NI coil. We verified this method on several solder impregnated no-insulation coils (SINoInCs) to excite their field with different rates, for which the field delay with normal charging method could be very large because of the very low inter-turn resistance. The test results show that this kind of fast excitation method could successfully achieve the desired field with high accuracy and mitigate the field delay from 130 s to almost 0 s. Besides, the large overshoot current introduced by the fast charging does not quench the coils even with an overshoot current which is almost double of the coils’ operating current.

Research on current harmonic suppression of permanent magnet synchronous motor using smith predictive controller

Abstract Due to the dead time added to the operation of the motor inverter, the generated current harmonics are introduced into the synchronous motor, increasing the harmonic content of the motor. The higher harmonic content is the 5th, 7th, 11th, and 13th current harmonics, which can cause motor torque ripple [1]. To suppress the current harmonics that cause torque ripple, a control method of using a PI controller and a quasi-proportional resonant controller in parallel is considered to suppress current harmonics. However, the introduction of a proportional resonant controller can cause greater overshoots in the current response, and external environmental influences can also generate current disturbances. Therefore, a method based on Smith prediction-PID and quasi-proportional resonance controller cascade control structure is proposed to suppress current harmonics and current overshoot in response to this problem. Finally, the effectiveness of this method was verified through simulation experiments, thereby improving the stability of synchronous motor operation.

Investigation into active‐gate‐driving performance and potential closed‐loop controller implementations for silicon carbide MOSFET modules

AbstractActive gate driving (AGD) is a promising concept for achieving high‐performance power transistor switching. This is particularly crucial for Silicon Carbide (SiC) MOSFETs since their inherently fast switching characteristics give rise to severe overshoots and oscillations which translate into increased levels of electromagnetic interference (EMI) emissions. In this paper, an AGD strategy using a single‐pulse applied during the switching transient is considered for a 1200 V 400 A SiC MOSFET module. The effect of single‐pulse timing, load current, and temperature on the switching performance is analyzed in detail. The radiated EMI reduction benefits are quantified by H‐field and E‐field probes. A conceptual closed‐loop AGD approach is presented and compared to open‐loop operation. For the transistor turn‐off case under full load current of 400 A, experimental results show that it is possible to reduce voltage overshoot by 43.3%, voltage and current oscillations by 69.7% and 52.2% respectively, and EMI by 76.6%, with a trade‐off in the switching energy by a relatively minor increase of 18.2%, compared to the conventional gate driving case. For the turn‐on case, current overshoot was reduced by 32.7%, EMI by 52%, voltage and current oscillations by 54.6% and 52.8%, respectively, with a penalty of 50.9% increase in the switching loss.

SiC MOSFET Active Gate Drive Circuit Based on Switching Transient Feedback

Due to the influence of parasitic internal parameters and junction capacitance, the silicon carbide (SiC) power devices are frequently marred by significant overshoots in current and voltage, as well as high-frequency oscillations during the switching process. These phenomena can severely compromise the reliability of SiC-based power electronic converters during operation. This study delves into the switching transient of the SiC MOSFET with the goal of establishing a quantitative correlation between the gate driving current and the overshoot in both the drain-source voltage and the drain current. In light of these findings, the innovative active gate drive (AGD) circuit, which features an adjustable gate current, is introduced. Throughout the switching process, the AGD circuit employs a dynamic monitoring and feedback mechanism that is responsive to the gate voltage and rate of change in the drain-source voltage and drain current of the SiC MOSFET. This adjustment enables gate driving current to be actively modified, thereby effectively mitigating the occurrence of overshoots and oscillations. To empirically validate the efficacy of the proposed AGD circuit in curbing voltage and current overshoots and oscillations, a double-pulse experimental setup was meticulously constructed and tested.

Digital Close-Loop Active Gate Driver for Static and Dynamic Current Sharing of Paralleled SiC MOSFETs

SiC power devices have been extensively for the high-power density application scenarios. To increase the current rating, SiC devices are usually connected in parallel. However, the mismatching current brought by unbalanced electrical parameters can increase the current stress of a device and pose reliability concern of the converter system. Aiming at addressing the current imbalance for paralleled SiC devices, this paper reports the application of an improved active gate driver (AGD) on the paralleled SiC MOSFETs to address the current imbalance problems. The three-level driver voltage can minimize the overshoot voltage and current. The adjustable turn-on voltage and gate signal delay time can realize the current sharing of both static and dynamic process. Current sensors and a digital controller are utilized for close-loop control. The functionality of the proposed AGD is validated in continuous operating experiment.

Marine heatwaves and cold spells in the Brazil Overshoot show distinct sea surface temperature patterns depending on the forcing

The Brazil Current Overshoot regions feature the strongest sea surface temperature variations over the global ocean but forecast skill for these extreme variations is limited. Here we investigate the drivers of marine heatwaves and cold spells in this region and find that ocean flows and sea surface heat fluxes are the primary drivers. We also find that sea surface temperature extremes driven by air-sea heat fluxes produce consistent changes in sea surface temperature and related atmospheric variables over a wide horizontal area, whereas ocean flow-driven sea surface temperature extremes exhibit low consistency in air variables and limited consistency in the spatial extent of sea variables across most sea surface temperature extreme events. These differing air-sea characteristics associated with extremes driven by different drivers offer potential avenues for improving prediction skills and advancing the understanding of three-dimensional air-sea impacts associated with extreme events.

Ballistic performance and overshoot effects in gallenene nanoribbon field-effect transistors

Gallenene is a novel metallic 2D material that can provide a semiconducting counterpart if patterned into quasi-one-dimensional (quasi-1D) nanostructures, i.e., gallenene nanoribbons (GaNRs). We investigate semiconducting GaNRs as a potential channel material for future ultrascaled field-effect transistors (FETs) by employing quantum transport simulations based on Green's functions and tight-binding Hamiltonians with the orbital resolution calibrated on ab initio calculations. The impact of GaNR width downscaling from ∼6 nm down to ∼0.2 nm on the electronic, transport, and ballistic device properties is investigated for the FET channel length of 15 nm. We report current enhancement and injection velocity overshoot effects for sub-1.2 nm-wide nFETs and pFETs, with a maximum current increase of 53% in the 1.2 nm-wide GaNR pFET in comparison to the widest device. In addition, promising current-driving capabilities of n- and p-channel GaNR FETs are observed with top ballistic currents of more than 2.2 mA/μm and injection velocities of up to 2.4 × 107 cm/s. The reported data are explained by analyzing the evolution of band structure and related parameters such as injection velocity, quantum capacitance, effective transport mass etc., with increasing quantum confinement effects in ultranarrow GaNRs. Generally, we find that quasi-1D gallenene is a promising channel material for future nanoscale FETs, especially for transistor architectures based on stacked nanosheets.

State feedback control of four-phase interleaved boost converter combined with PEM fuel cell

In this paper, a state feedback controller is designed for a four-phase interleaved dc-dc boost converter connected to PEM fuel cell to regulate the output voltage and current around desired values. The proposed controller features two loops based on state feedback, transforming the system into a state representation. The synthesis of the controller gains is validated using the Linear Quadratic Regulator (LQR) technique. To demonstrate its effectiveness, a typical proportional-integral (PI) controller based on the same average modelling is designed for further comparison and discussion. The performance metrics, including output voltage, source current ripples, settling time, and overshoot showcase the high robustness and dynamic characteristics of the proposed controller.The simulations are conducted using Matlab Simulink with a 1kW fuel cell system.

Robust Integral Terminal Sliding Mode Control of three phase voltage source converter for PV Grid Connected System

This paper proposes a robust integral terminal sliding mode control (ITSMC) strategy for a three-phase two-level voltage source converter used in photovoltaic power generation systems. The main goal of the proposed controller is to steer the system state along a predefined sliding surface while mitigating the chattering phenomenon. This development aims to significantly improve system performance by reducing overshoots and solving real-world PV challenges such as irradiation fluctuations, all while achieving a faster dynamic response. To demonstrate the robustness of the ITSMC controller, it is subjected to varying irradiation levels and measurement noise. MATLAB/Simulink software is employed for simulation and validation of the proposed system. Comparative analysis reveals that the proposed controller outperforms conventional sliding mode controller in terms of current overshoots and dynamic response. These findings demonstrate compliance with the criteria outlined in IEEE Std 519-2014.

Impact of heavy ions on a-Si:H/PolySi bilayer thin film transistors with Schottky barrier source and drain based on Nickel Silicide

This study investigates the influence of heavy ion irradiation on thin film transistors (TFTs) based on an a-Si:H/PolySi active layer and Schottky barrier-based source and drain. Through the use of Technology Computer-Aided Design (TCAD) simulations, we analyze the impact on device performance. We examine the ambipolar device characteristics by varying the thickness of the active layer (Poly-Si) and studying the corresponding physics. Our results reveal that reducing the active layer thickness from 140 to 80 nm decreases the magnitude of the threshold voltage (|VT|) for both nMOS and pMOS operating voltages. Additionally, the subthreshold slope is reduced for both nMOS and pMOS as the active layer thickness is decreased from 140 to 80 nm.Further, we investigated the transient response of the drain current to heavy ion irradiation in the sensitive regions across the Schottky barrier-based source and drain. We specifically analyze the phenomenon of bipolar amplification for various Linear Energy Transfer (LET) values, ranging from 0.1 MeV cm2/mg to 100 MeV cm2/mg. Our findings indicate that increasing the LET values from 0.1 MeV cm2/mg to 100 MeV cm2/mg results in amplified bipolar behavior and a drain current overshoot of over 10 % for both pMOS and nMOS operating voltages. To summarize, this work highlights the effects of heavy ion irradiation on TFTs with an a-Si:H/PolySi active layer and Schottky barrier-based source and drain. The study explores the influence of active layer thickness on device characteristics and demonstrates the transient response of drain current under different LET values. These findings contribute to a better understanding of the behavior and performance of TFTs subjected to heavy ion irradiation.

Preliminary investigation on the implementation of an artificial synapse using TaOx-based memristor with thermally oxidized active layer.

This study presents a preliminary exploration of thermally oxidized TaOx-based memristors and their potential as artificial synapses. Unlike the 10-minannealed devices, which display instability due to current overshoots, the 5-minannealed device exhibits stable resistive switching, retention, and endurance characteristics. Moreover, our memristor showcases synaptic behaviors encompassing potentiation, depression, spike-timing-dependent plasticity, and excitatory postsynaptic currents. This synaptic emulation holds tremendous promise for applications in neuromorphic computing, offering the opportunity to replicate the adaptive learning principles observed in biological synapses. In addition, we evaluate the device's suitability for pattern recognition within a neural network using the modified National Institute of Standards and Technology dataset. Our assessment reveals that the Pt/TaOx/Ta memristor with an oxidized insulator achieves outstanding potential manifested by an accuracy of 93.25% for the identical pulse scheme and an impressive accuracy of 95.42% for the incremental pulse scheme.

A Junction Temperature and Package Aging Decoupling Evaluating Method for SiC MOSFETs Based on the Turn-on Drain-Source Current Overshoot

A Junction Temperature and Package Aging Decoupling Evaluating Method for SiC MOSFETs Based on the Turn-on Drain-Source Current Overshoot

Design and performance analysis of cascaded pseudo derivative feedback plus pseudo derivative feedforward controller for PMSM drive

PurposeThis paper aims to present a cascaded pseudo derivative feedback (PDF) plus pseudo derivative feedback plus pseudo derivative feedforward (PDFF) controller for a permanent magnet synchronous motor (PMSM) to improve the transient response of the system.Design/methodology/approachProportional integral (PI) plus PI controller and the proposed PDF plus PDFF controller are designed, stability analysis is performed using the extended root locus method, and the effect of the damping coefficient is also extensively studied to validate the robustness of the proposed controller.FindingsWhen compared to a cascaded PI plus PI controller, the proposed control approach has a much shorter settling time for the entire system and a 50% reduction in overshoot in stator current under extensive variations in speed with load disturbance.Originality/valueThe proposed controller is programmed into an FPGA Altera Cyclone II and applied to a 1.5 kW laboratory prototype PMSM drive. The effectiveness of the proposed methods has been demonstrated experimentally throughout a wide variable speed range, from 0 to 157 rad/s at different load conditions.

Multifilamentary switching of Cu/SiOx memristive devices with a Ge-implanted a-Si underlayer for analog synaptic devices

Various memristive devices have been proposed for use in neuromorphic computing systems as artificial synapses. Analog synaptic devices with linear conductance updates during training are efficiently essential to train neural networks. Although many different analog memristors have been proposed, a more reliable approach to implement analog synaptic devices is needed. In this study, we propose the memristor of a Cu/SiOx/implanted a-SiGex/p++ c-Si structure containing an a-Si layer with properly controlled conductance through Ge implantation. The a-SiGex layer plays a multifunctional role in device operation by limiting the current overshoot, confining the heat generated during operation and preventing the silicide formation reaction between the active metal (Cu) and the Si bottom electrode. Thus, the a-SiGex interface layer enables the formation of multi-weak filaments and induces analog switching behaviors. The TEM observation shows that the insertion of the a-SiGex layer between SiOx and c-Si remarkably suppresses the formation of copper silicide, and reliable set/reset operations are secured. The origin of the analog switching behaviors is discussed by analyzing current-voltage characteristics and electron microscopy images. Finally, the memristive-neural network simulations show that our developed memristive devices provide high learning accuracy and are promising in future neuromorphic computing hardware.

Enhancing EV charger resilience with reinforcement learning aided control

This study aims to improve the performance of sustainable electric vehicle chargers in the face of unpblackictable/unpreventable disturbances. Over the past few years, Dual Active Bridge (DAB) DC-DC Converters are procuring substantial recognition for electric vehicle charging applications due to their superior characteristics such as higher power density, bidirectional mode of operation, and higher efficiency. Unexpected disturbances and fault scenarios at both source and load sides can deteriorate DAB converters’ performance. In this study, the performance of a single-phase shifted DAB converter is enhanced to achieve desiblack output current under several disturbance conditions for electric vehicle (EV) charging applications. A Reinforcement Learning (RL) based Deep Deterministic Policy Gradient (DDPG) algorithm is deployed to proactively tune control parameters when the DAB undergoes certain unexpected disturbances including short circuit faults at the source and battery sides. Results show that the RL-tuned PI controller improves the rate of current overshoot significantly compablack with the manually-tuned PI controller. The method and results are validated through simulations in MATLAB/Simulink environment.

Optimal Sliding-Mode Control of Semi-Bridgeless Boost Converters Considering Power Factor Corrections

Sliding-mode control (SMC) is a robust technique used in power electronics (PE) for controlling the behavior of power converters. This paper presents simulations and experimental results of an optimal SMC strategy applied to Semi-Bridgeless Boost Converters (SBBC), which includes Power Factor Correction (PFC). As the main contribution, the optimal coefficients of the SMC strategy are obtained using two metaheuristic approaches, namely the Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). The main objective is to obtain the sliding coefficients that ensure the best converter response in terms of the input current and output voltage, both during start-up and under disturbances (including changes in load, source, and references). The fitness function to be minimized includes two coefficients, namely the Integrative Absolute Error (IAE) and the Integral Time Absolute Error (ITAE), for both the input current and output voltage. These coefficients measure the converter’s effort to follow the control references. The IAE penalizes errors during start-up, whereas the ITAE penalizes errors in the steady state. The tests carried out demonstrated the effectiveness of the GA and PSO techniques in the optimization process; nonetheless, the GA outperformed the PSO approach, providing sliding coefficients that allowed for a reduction in the input current overshoot during start-up of up to 24.15% and a reduction in the setting time of the output voltage of up to 99%. The experimental results were very similar when tuning with the GA and PSO techniques; nevertheless, tuning with the GA technique produced a better response in the face of disturbances compared to the PSO technique.