Blar i Institutt for teknisk kybernetikk på forfatter "Cai, Xu"
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On the Equivalence and Impact on Stability of Impedance Modeling of Power Electronic Converters in Different Domains
Rygg, Atle; Molinas Cabrera, Maria Marta; Chen, Zhang; Cai, Xu (Journal article, 2017)Small-signal analysis of power electronic converters and systems is often carried out by impedance-based methods. At the core of these methods lies the impedance modeling, which can either be obtained through analytical ... -
On the Impedance Modeling and Equivalence of AC/DC Side Stability Analysis of a Grid-tied Type-IV Wind Turbine System
Zhang, Chen; Molinas Cabrera, Maria Marta; Rygg, Atle; Cai, Xu (Journal article; Peer reviewed, 2018)Impedance modeling of a Type-IV wind turbine is usually associated with model reductions, e.g. the grid-side converter (GSC) is modeled in detail, whereas the machine-side converter (MSC) is simplified as a constant power ... -
Optimal Design of Controller Parameters for Improving the Stability of MMC-HVDC for Wind Farm Integration
Lyu, Jing; Cai, Xu; Molinas Cabrera, Maria Marta (Journal article, 2017)A subsynchronous oscillation (SSO) phenomenon has been observed in a modular multilevel converter-based high-voltage DC (MMC-HVDC) transmission system for wind farm integration in the real world, which is independent of ... -
Properties and Physical Interpretation of the Dynamic Interactions between Voltage Source Converters and Grid: Electrical Oscillation and Its Stability Control
Zhang, Chen; Molinas Cabrera, Maria Marta; Rygg, Atle; Li, Zheng; Cai, Xu (Journal article; Peer reviewed, 2017)Voltage source converters (VSCs) play an important role in the power conversion of renewable power generation (RPG) systems. Conventional power systems are considerably affected by power electronic devices in systems with ... -
Sequence Domain SISO Equivalent Models of a Grid-tied Voltage Source Converter System for Small-Signal Stability Analysis
Zhang, Chen; Molinas Cabrera, Maria Marta; Rygg, Atle; Cai, Xu (Journal article; Peer reviewed, 2017)This paper presents a generalized method for converting multi-input and multi-output (MIMO) dq impedance model of a grid-tied voltage source converter system into its sequence domain single-input and single-output (SISO) ... -
Stabilization control methods for enhancing the stability of wind farm integration via an MMC-based HVDC system
Lyu, Jing; Molinas Cabrera, Maria Marta; Cai, Xu (Book, 2017)The subsynchronous oscillation (SSO) phenomenon may occur in a modular multilevel converter-based high-voltage dc (MMC-HVDC) transmission system for wind farm integration, which has already been observed in the real world. ... -
Subsynchronous Oscillation Mechanism and Its Suppression in MMC-Based HVDC Connected Wind Farms
Lyu, Jing; Cai, Xu; Amin, Mohammad; Molinas Cabrera, Maria Marta (Journal article, 2017)A subsynchronous oscillation (SSO) phenomenon in a wind farm integrated with a modular multilevel converter (MMC)-based high-voltage direct current (HVDC) transmission system has been recently observed in the real world. ... -
Synchronizing Stability Analysis and Region of Attraction Estimation of Grid-Feeding VSCs Using Sum-of-Squares Programming
Zhang, Chen; Molinas Cabrera, Maria Marta; Zheng, Li; Cai, Xu (Peer reviewed; Journal article, 2020)Grid-synchronizing Stability (GSS) is an emerging issue related to grid-feeding voltage-source converters (VSCs). Its occurrence is primarily related to the non-linear dynamics of a type of vastly applied synchronization ... -
Understanding the Nonlinear Behaviour and Synchronizing Stability of a Grid-Tied VSC Under Grid Voltage Sags
Zhang, Chen; Molinas Cabrera, Maria Marta; Lyu, Jing; Zong, Haoxiang; Cai, Xu (Chapter, 2019)Transients of a typical grid synchronizing VSC are closely associated with the over-current and over-voltage in circuits. Previous analysis in evaluating such transient phenomenon usually ignore the nonlinear control effects ...