Papers by Keyword: Small Signal

Abstract: SiC heteropolytype structures indicate important applications in high frequency, large power solid devices etc. In this paper, the impact avalanche transit time (IMPATT) and mixed tunneling avalanche transit time (MITATT) diodes with heteropolytype consisting of two semiconductors among the 3C-SiC, 4H-SiC and 6H-SiC are numerically simulated to investigate the static state and small signal characteristics at the atmospheric window frequency of 1.56 THz. The breakdown voltage, avalanche voltage, peak value of static electric field, the maximum generation rates of avalanche and tunneling, power conversion efficiency, admittance-frequency relation of the proposed SiC heteropolytype diodes are calculated, respectively. Comparing the obtained parameters of IMPATT diodes with those of MITATT devices, the results imply that tunneling shows little influence on the small signal performance of the heteropolytype IMPATT diodes included 3C-SiC material, which is different from those of the homopolytype counterparts.

Abstract: In photovoltaic power systems, both photovoltaic modules and switching-mode converters present nonlinear and time-variant characteristics, which result in a difficult control problem. This paper presents an in-depth analysis and modeling to discover the inherent features of a photovoltaic (PV) power system and proposes a control method for PV power system based on small-signal model. This paper also presents a state equation and transfer function of PV power system and a stable control system for regulating the photovoltaic voltage. Simulation and experiment results demonstrate the effectiveness of the presented analysis, design, and implementation.

Abstract: In recent years， as the load increasing gradually，problems in voltage stability of regional power network which is the terminal of power grid is serious. From the voltage stability machine rational analysis to roll out small interfering voltage stability criterion of new, and the modal method is used to determine the key nodes and areas of the system theory basis.