Transient electrothermal simulation of power semiconductor devices

In this paper, a new thermal model based on the Fourier series solution of heat conduction equation has been introduced in detail. 1-D and 2-D Fourier series thermal models have been programmed in MATLAB/Simulink. Compared with the traditional finite-difference thermal model and equivalent RC thermal network, the new thermal model can provide high simulation speed with high accuracy, which has been proved to be more favorable in dynamic thermal characterization on power semiconductor switches. The complete electrothermal simulation models of insulated gate bipolar transistor (IGBT) and power diodes under inductive load switching condition have been successfully implemented in MATLAB/Simulink. The experimental results on IGBT and power diodes with clamped inductive load switching tests have verified the new electrothermal simulation model. The advantage of Fourier series thermal model over widely used equivalent RC thermal network in dynamic thermal characterization has also been validated by the measured junction temperature

Introduction: Redemptive Societies in Cultural and Historical Context

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Introduction: redemptive societies as Confucian NRMs?

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Physical Investigation into Effective Voltage Balancing by Temporary Clamp Technique for the Series Connection of IGBTs

The series connection of IGBTs is essential for high-voltage applications where fast switching performances need to be maintained. However, unbalanced voltage sharing is a major resistance to the converter application of this structure. There are a number of causes leading to voltage unbalance, such as different signal delays, parasitic parameters, tail currents, and so on. A temporary clamp scheme performed by active voltage control (AVC) has been proven to be effective in solving the unbalanced voltage-sharing issue. However, the basic physics has not been investigated. In this paper, the physical principle of voltage unbalance within IGBTs series operation is discussed. The carrier storage region differences are concluded to be the intrinsic cause of unbalanced voltage sharing. By using an accurate Fourier-series-based IGBT simulation model with appropriate assumptions, a physical explanation for temporary clamp is provided in detail. At the end of the tail current period when the excess carrier concentration becomes close to the intrinsic doping density, the temporary clamp is able to achieve satisfactory equal voltage sharing

Introduction: The Emergence of Academic Research on Redemptive Societies

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導言：關於“救世團體”： “鄉村宗教” 還是 “邪教”？

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Robust stability analysis of active voltage control for high-power IGBT switching by Kharitonov's theorem

The main idea of active voltage control (AVC) is to employ classic feedback-control methods forcing the IGBT collector voltage transient to follow a predefined trajectory. This feedback control of IGBTs has great advantages in guaranteeing that IGBTs remain in safe operating area (SOA), restricting EMI, mitigating the voltage/current stress, minimizing/predicting their power losses, and balancing voltages of IGBTs in series. Inevitably, however, AVC introduces stability issues. Based on the assumption that accurate IGBT small-signal model parameters are available, an analogue proportional-derivative and multiloop feedback control was proposed to achieve stable performance in previous work. Due to nonlinearities and uncertainties in IGBT parameters, previous stability analysis methods have important limitations. This work uses Kharitonov's theorem during the IGBT controlled turn-off to assess the system's stability and guide the AVC design to account for model uncertainties and varying parameters. We conducted experiments to investigate the system's robust stability due to these uncertainties in the IGBT parameters, which confirm the validity of the proposed theoretical analysis. With the use of wide bandwidth op-amps, it is shown that the feedback design may be simplified

Physics-based Compact Model of Integrated Gate-Commutated Thyristor with Multiple Effects for High Power Application

This paper presents a physics-based compact model of integrated gate-commutated thyristor (IGCT) with multiple effects for high power application. The proposed model has both acceptable accuracy and computation time requirement, which is suitable for system level circuit simulation and IGCT’s whole wafer modelling work. First, the development of IGCT model is discussed and the one-dimension phenomenon of IGCT is analyzed in the paper. Second, a physics-based compact model of IGCT is proposed. The proposed model of IGCT includes multiple physical effects that are crucial to IGCTs working in high power applications. These physical effects include the impact ionization effect, moving boundary of depletion region during punch-thourgh (PT) and the local lifetime region. The Fourier series solution is applied for the ambipolar diffusion equation in the base region. Third, the proposed model is implemented in Simulink and compared with the model in Silvaco Atlas, a finite-element (FEM) tool. Finally, the proposed compact model of IGCT is validated by experiments

Study protocol : the empirical investigation of methods to correct for measurement error in biobanks with dietary assessment

Peer reviewedPublisher PD

Elucidating the aetiology of human Campylobacter coli infections

Peer reviewedPublisher PD