Monolithic GaN power IC has been regarded as the ultimate solution to unlock the full potential of the wide bandgap GaN technology for next-generation high-speed, high-efficiency and high-density power circuits. Howev...
Monolithic GaN power IC has been regarded as the ultimate solution to unlock the full potential of the wide bandgap GaN technology for next-generation high-speed, high-efficiency and high-density power circuits. However, with scarce power device options, the current development of monolithic GaN power ICs faces severe design challenges. A critical example can be found in the design of one of the most important circuit modules – the voltage level shifter, which is the enabler to drive any kind of high-side power switch in a power circuit. To overcome this challenge, this paper proposes a new circuit structure and a novel operation concept of a dynamic floating voltage level shifter to reduce propagation delays, improve dynamic slew rates and attain superb dv⁄dt noise immunity for both speed and reliability improvements. Implemented on a 200V, 180nm, n-type only, GaN-on-SOI process, the proposed voltage level shifter only occupies a die area of 0.12mm 2 and achieves 2.81ns rising and 3.44ns falling propagation delays at room temperature with a slew rate of 100V/ ns.
The use of wind power is rapidly growing worldwide as a means of reducing carbon emissions for the energy *** has the world’s largest wind power installation and multiple large-scale wind farm clusters,each comprisin...
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The use of wind power is rapidly growing worldwide as a means of reducing carbon emissions for the energy *** has the world’s largest wind power installation and multiple large-scale wind farm clusters,each comprising dozens of wind *** the planning and operation of the powersystem,it is important to understand the power fluctuation characteristics of wind farm *** studies demonstrate that the relative power fluctuation of a wind farm cluster is less than that of a single wind *** this decreasing trend a random occurrence or does it have a regular pattern?This scientific question is addressed by investigating the mechanism of the cumulative effect of a wind farm *** this study,a cumulative model is proposed by examining the spatiotemporal relationships of wind power variations and wind farm *** gain function and critical cumulative frequency are defined as the foundations to analytically describing the cumulative *** investigating the cumulative effect mechanism,the relationship between power fluctuation and spatiotemporal parameters of the wind farm cluster are *** power fluctuation of a cluster can be predicted using the cumulative model even before it is completely *** mechanism of the cumulative effect is validated on the basis of the data of two actual wind farm clusters.
Multi-level power converters today are highly desirable for high step-down DC-DC conversions but face a serious challenge due to the inherent limitations of topology and operation, which severely impacts efficiency. T...
Multi-level power converters today are highly desirable for high step-down DC-DC conversions but face a serious challenge due to the inherent limitations of topology and operation, which severely impacts efficiency. To combat this challenge, this paper proposes a new operation strategy - tri-path synchronous rectification (TSR) to reduce conduction loss in each discharge phase significantly, which is regarded as a dominant factor to efficiency. The TSR strategy is non-intrusive and can be virtually applied to any multi-level converters without interrupting the original converter operation. To demonstrate the design ideas, a 4-level TSR converter prototype is designed and tested. It down-converts a 48V power source to an output voltage programmable from 1V to 2V with a maximum load of 25A and a peak efficiency of 90.8%.
In an effort to comply with stringent electromagnetic interference (EMI) standards for automotive electronics applications, this paper introduces a new SEPIC converter topology with significantly reduced di/dt switchi...
In an effort to comply with stringent electromagnetic interference (EMI) standards for automotive electronics applications, this paper introduces a new SEPIC converter topology with significantly reduced di/dt switching dynamics for conducted EMI suppression. The converter employs a unique T circuit network, consisting of a coupled inductor and an auxiliary LC branch, to self-cancel its input current ripple ΔI IN , thus minimizing associated di/dt. By doing so, the converter incurs no significant power density and efficiency penalties. Meanwhile, the converter requires no active control circuitry to ensure accurate ΔI IN cancelation, simplifying the design complexity. To demonstrate the converter topology and design ideas, a converter prototype is designed, which accommodates a wide input supply voltage range of 4.5V to 40V and delivers an output of 12V, with seamless buck-boost conversion operation. Operating at 400kHz, it delivers a maximum power of 42W and achieves a peak efficiency of 86.8%. For the step-up conversion with 5V V IN and 500mA load, the ΔI IN self-canceled SEPIC topology achieves 9.6dB peak EMI reduction at the fundamental frequency. For the step-down conversion with 1.5A load, it reduces the peak EMI by 20.4dB and 13.9dB at V IN of 24V and 40V, respectively, satisfying the CISPR25 Class 2 Standards.
This paper proposes a vehicle-to-grid(V2G)system interfaced with a microgrid that is effective at regulating frequency on a microgrid over a 24-h cycle.A microgrid is designed and divided into four *** first component...
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This paper proposes a vehicle-to-grid(V2G)system interfaced with a microgrid that is effective at regulating frequency on a microgrid over a 24-h cycle.A microgrid is designed and divided into four *** first component is a diesel generator,which is used to act as the base power *** second component consists of renewable energy(RE)power plants,which include solar photovoltaic(PV)and wind *** third component is a V2G *** last component is the load connected to the microgrid.A microgrid is designed to be of sufficient size to represent a community of one thousand households during the day period of low consumption in the spring or fall seasons.A hundred electric vehicles(EVs)are modeled as base models to realize a 1:10 ratio for cars to households,which indicates a possible scenario in the near *** analysis of the active power,reactive power,voltage,frequency,and current is carried *** is established that the proposed design of the V2G andmicrogrid effectivelymaintains systemparameters such as frequency and voltage within permissible limits with an error of less than 1%.Further,transient deviations in these parameters are limited to within 5%.A microgrid with V2G devices regulates the system frequency by mitigating load demand through coordinated control of conventional generation,solar PV plant generation,wind plant generation,power exchange with the microgrid network,and electric *** proposed microgrid and V2G are efficient for energy management and mitigation of intermittency and variability of RE power with improved *** in system parameters have been investigated by changing the operating scenario,and it has been determined that the error is limited to less than 5%.The study is effectively realized in the MATLAB/Simulink environment.
Weak grid connection is one of the main causes for the sub-synchronous oscillations (SSOs) of renewable power generation systems (RPGSs). In this paper, the allocation of distributed synchronous condensers (DSCs) is o...
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To overcome the shortcomings of model-driven state estimation methods, this paper proposes a data-driven robust state estimation (DDSE) method through off-line learning and on-line matching. At the off-line learning s...
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To overcome the shortcomings of model-driven state estimation methods, this paper proposes a data-driven robust state estimation (DDSE) method through off-line learning and on-line matching. At the off-line learning stage, a linear regression equation is presented by clustering historical data from supervisory control and data acquisition (SCADA), which provides a guarantee for solving the over-learning problem of the existing DDSE methods;then a novel robust state estimation method that can be transformed into quadratic programming (QP) models is proposed to obtain the mapping relationship between the measurements and the state variables (MRBMS). The proposed QP models can well solve the problem of collinearity in historical data. Furthermore, the off-line learning stage is greatly accelerated from three aspects including reducing historical categories, constructing tree retrieval structure for known topologies, and using sensitivity analysis when solving QP models. At the on-line matching stage, by quickly matching the current snapshot with the historical ones, the corresponding MRBMS can be obtained, and then the estimation values of the state variables can be obtained. Simulations demonstrate that the proposed DDSE method has obvious advantages in terms of suppressing over-learning problems, dealing with collinearity problems, robustness, and computation efficiency.
Optimal allocation of synchronous condensers is one of the most-commonly-used ways to improve the operation performance of renewable power generators in weak grid. However, except for optimality, equity of the allocat...
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High proportion of renewable energy brings great challenges to the stable operation of the distribution network. Distributed energy storage (DES), as an interactive Lithium-ion battery energy storage system, can effec...
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This study introduces a multi-scale convolutional neural network (MCNN) for diagnosing various faults in proton exchange membrane fuel cell (PEMFC) systems. Using simulated fault data from a 240 kW PEMFC stack, the MC...
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