• Title, Summary, Keyword: Small-signal analysis

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Modeling and Small-Signal Analysis of Controlled On-time Boost Power Factor Correction Circuit (도통 시간 제어형 승압형 역률보상회로의 모델링과 소신호 해석)

  • Park, Hyo-Gil;Hong, Seong-Su;Choe, Byeong-Jo
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.49 no.5
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    • pp.364-370
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    • 2000
  • A large-signal average model for the controlled on-time boost power factor correction(PFC) circuit is developed and subsequently linearized resulting in a small-signal model for the PFC circuit. Ac analyses are performed using the small-signal model, revealing new results new on small-signal dynamics of the PFC circuit. The analysis results and model predictions are confirmed with experimental measurements on 200W prototype PFC circuit.

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Small Signal Stability Analysis of Doubly Fed Induction Generator including SDBR

  • Shawon, Mohammad Hasanuzzaman;Al-Durra, Ahmed;Caruana, Cedric;Muyeen, S.M.
    • Journal of international Conference on Electrical Machines and Systems
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    • v.2 no.1
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    • pp.31-39
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    • 2013
  • This paper presents small signal stability analysis of a doubly fed induction generator (DFIG) based wind farm including series dynamic braking resistor (SDBR) connected at the stator side. A detailed mathematical model of wind turbine, DFIG machine and converters and SDBR is presented in this paper to derive the complete dynamic equations of the studied system. Small signal stability of this system is carried out by modal and sensitivity analysis, participation factors and eigenvalue analysis. Finally, this paper presents an analysis of the dynamic behavior of DFIG based wind farm under voltage dip condition with and without SDBR.

Analysis of Small Signal Stability Using Resonance Conditions (공진조건을 이용한 미소신호 안정도 해석)

  • Cho, Sung-Jin;Jang, Gil-Soo;Yoon, Tae-Woong
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.51 no.11
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    • pp.535-543
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    • 2002
  • Modern power grids are becoming more and more stressed with the load demands increasing continually. Therefore large stressed power systems exhibit complicated dynamic behavior when subjected to small disturbance. Especially, it is needed to analyze special conditions which make small signal stability structure varied according to operating conditions. This paper shows that the relation between small signal stability structure varied according to operating conditions. This paper shows that the relation between small signal stability and operating conditions can be identified well using node-focus point and 1:1 resonance point. Also, the weak point which limits operating range is found by the analysis of resonance condition, and it is shown that reactive power compensation may solve the problem in the weak points. The proposed method is applied to test systems, and the results illustrate its capabilities.

Small signal stability analysis of power systems with non-continuous operating elements by using RCF method : Modeling of the state transition equation (불연속 동작특성을 갖는 전력계통의 RCF법을 사용한 미소신호 안정도 해석 : 상태천이 방정식으로의 모델링)

  • Kim Deok Young
    • Proceedings of the KIEE Conference
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    • pp.342-344
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    • 2004
  • In conventional small signal stability analysis, system is assumed to be invariant and the state space equations are used to calculate the eigenvalues of state matrix. However, when a system contains switching elements such as FACTS devices, it becomes non-continuous system. In this case, a mathematically rigorous approach to system small signal stability analysis is by means of eigenvalue analysis of the system periodic transition matrix based on discrete system analysis method. In this research, RCF(Resistive Companion Form) method is used to analyse small signal stability of a non-continuous system including switching elements'. Applying the RCF method to the differential and integral equations of power system, generator, controllers and FACTS devices including switching elements should be modeled in the form of state transition matrix. From this state transition matrix eigenvalues which are mapped to unit circle can be calculated.

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Small-Signal Modeling and Controller Design of Grid-Connected Inverter for Solid State Transformer (반도체 변압기용 단상 계통 연계형 인버터의 소신호 모델링과 제어기 설계)

  • Kim, Bo-Gyeong;Lee, Jun-Young;Lee, Soon-Sinl;Jung, Jee-Hoon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.1
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    • pp.40-47
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    • 2017
  • In this paper, a small signal model for grid-connected inverter with unipolar pulse width modulation method is presented. Small-signal analysis allows to predict the stability and dynamics of the inverter. To regulate output voltage and to achieve power factor correction, inverter has two control loops. Loop gains are useful to identify the stability for multi-loop controlled system. Based on small-signal model, controllers are designed to improve audio susceptibility and output impedance characteristics. Proposed small-signal model and controllers are verified by PSIM simulation and experiments.

Universal SSR Small Signal Stability Analysis Program of Power Systems and its Applications to IEEE Benchmark Systems

  • Kim, Dong-Joon;Nam, Hae-Kon;Moon, Young-Hwan
    • KIEE International Transactions on Power Engineering
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    • v.3A no.3
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    • pp.139-147
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    • 2003
  • The paper presents a novel approach of constructing the state matrix of the multi-machine power system for SSR (subsynchronous resonance) analysis using the linearized equations of individual devices including electrical transmission network dynamics. The machine models in the local d-q reference frame are integrated with the network models in the common R-I reference frame by simply transforming their output equations into the R-I frame where the transformed output is used as the input to the network dynamics or vice versa. The salient feature of the formulation is that it allows for modular construction of various component models without rearranging the overall state space formulation. This universal SSR small signal stability program provides a flexible tool for systematic analyses of SSR small-signal stability impacts of both conventional devices such as generation systems and novel devices such as power electronic apparatus and their controllers. The paper also presents its application results to IEEE benchmark models.

A Unified Framework for Small Signal Stability Analysis of Power Systems and Its Application to Available Transfer Capability (계통의 종합적 미소신호 안정도 해석 알고리듬과 ATC 산정에의 응용에 관한 연구)

  • Kim, Sang-Ahm;Song, Hwa-Chang;Lee, Byong-Jun;Kwon, Sae-Hyuk
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.10
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    • pp.1222-1230
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    • 1999
  • This paper presents the framework for analysis of small-signal stability. In this framework the equilibrium points of system DAE model are traced using continuation method and instability points are determined on the solution path. Especially Implicit shift QR-modified Arnoldi method is utilized to calculated the rightmost eigenvalues. Small-signal stability is becoming one of the major factors that affect the ATC in the environment of deregulation. Stability limited ATC is easily evaluated in this stability analysis process.

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Contingency Analysis of Small Signal Stability for MW Changes (발전량 변화와 미소신호안정도 상정사고 해석)

  • Shim, K.S.;Song, S.G.;Moon, C.J.;Kim, Y.G.;Nam, H.K.
    • Proceedings of the KIEE Conference
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    • pp.139-141
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    • 2002
  • This paper describes a new contingency analysis methods for small signal security assessment based on the eigenvalue perturbation. The eigenvalue perturbation with respect to MW changes can be used to find possible sources of the low frequency oscillation, and to select contingency for small signal stability. The proposed algorithm has been successfully tested on the KEPCO systems.

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Advanced Small-Signal Model of Multi-Terminal Modular Multilevel Converters for Power Systems Based on Dynamic Phasors

  • Hu, Pan;Chen, Hongkun;Chen, Lei;Zhu, Xiaohang;Wang, Xuechun
    • Journal of Power Electronics
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    • v.18 no.2
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    • pp.467-481
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    • 2018
  • Modular multilevel converter (MMC)-based high-voltage direct current (HVDC) presents attractive technical advantages and contributes to enhanced system operation and reduced oscillation damping in dynamic MMC-HVDC systems. We propose an advanced small-signal multi-terminal MMC-HVDC based on dynamic phasors and state space for power system stability analysis to enhance computational accuracy and reduce simulation time. In accordance with active and passive network control strategies for multi-terminal MMC-HVDC, the matchable small-signal stability models containing high harmonics and dynamics of internal variables are conducted, and a related theoretical derivation is carried out. The proposed advanced small-signal model is then compared with electromagnetic-transient and traditional small-signal state-space models by adopting a typical multi-terminal MMC-HVDC network with offshore wind generation. Simulation indicates that the advanced small-signal model can successfully follow the electromechanical transient response with small errors and can predict the damped oscillations. The validity and applicability of the proposed model are effectively confirmed.

Small-Signal Analysis of a Differential Two-Stage Folded-Cascode CMOS Op Amp

  • Yu, Sang Dae
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.14 no.6
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    • pp.768-776
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    • 2014
  • Using a simplified high-frequency small-signal equivalent circuit model for BSIM3 MOSFET, the fully differential two-stage folded-cascode CMOS operational amplifier is analyzed to obtain its small-signal voltage transfer function. As a result, the expressions for dc gain, five zero frequencies, five pole frequencies, unity-gain frequency, and phase margin are derived for op amp design using design equations. Then the analysis result is verified through the comparison with Spice simulations of both a high speed op amp and a low power op amp designed for the $0.13{\mu}m$ CMOS process.