A direct virtual power control algorithm is presented in this paper for VSC-HVDC startup. This control algorithm is based on direct power control (DPC) and expands the range of DPC. When the VSC converter AC side open circuit or the AC side current is zero, the control algorithm maintains the DPC feedback loop by introducing a virtual power, so that the DPC is able to control the AC output volt...

In this Space Vector PWM Control technique is designed for a three-phase voltage source converter (VSC) which act as a Static Synchronous Compensators to provide reactive power compensation. The VSC as STATCOM provide efficient damping for sub synchronous resonance that enhance the Power System Stability in addition to RPC. Among different Pulse width modulation techniques SVPWM technique is im...

The researches on direct AC-AC convertors have been an important field. The DC-modulated method, which was used in DC-DC convertors before, is used in AC-AC convertors to realize a direct AC-AC converting now. The method as regulating the duty of switch periods can control the circuit to output an acceptable sinusoid voltage wave. But this method can always bring forth a small phase shift betwe...

The paper considers the problem of implementing \Virtu-ally Synchronous Communication" in the primary partition of an asyn-chronous system. Virtually Synchronous Communication was rst introduced by the Isis system as a powerful mechanism for building fault-tolerant processes that mask failures by replication: it can be understood as a rule for ordering message deliveries (reliable multicasts) w...

VSC-HVDC is a fully controllable transmission device, allowing rapid and independent control of active power transmitted over the dc link and reactive power at each end of the dc link. Embedding VSC-HVDC in meshed ac networks opens up new possibilities to improve power grid reliability and efficiency. The general control architecture of VSC-HVDC system is presented with focus on converter contr...

Voltage-sourced converter (VSC) based FACTS controllers are capable of providing fast voltage support and active power flow control to improve the power transfer capability over congested transmission paths. In most published literature, a shunt VSC such as a Static Synchronous Compensator (STATCOM) is set to control the bus voltage and a series VSC such as a Static Synchronous Series Compensat...

A new methodology is presented to improve the design and tuning of a fuzzy logic controller (FLC) using variable structure control (VSC) theory. A VSC-type rule base is constructed and the fundamentals of FLC explored quantitatively by VSC theory. A very concise mathematical expression for the FLC is presented, in which the Lyapunov stability criterion can be applied to guide the design and tun...

This paper describes a novel reactive obstacle avoidance approach for mobile robot navigation in unknown and dynamic environment. This approach is developed based on the “situated-activity paradigm” and a “divide and conquer” strategy which steers the robot to move among unknown obstacles and towards a target without collision. The proposed approach entitled the Virtual Semi-Circles (VSC). The ...

 This paper presents an optimal design of Variable Structure Load Frequency Controller using Particle Swarm Optimization Algorithm. The optimal design provides a simple systematic way for obtaining optimum feedback gains and switching vector for VSC. It also includes a new method to reduce the chattering associated with the Variable Structure Controllers (VSC). The proposed method has been app...

BACKGROUND: ß -estradiol is a steroid sex hormone that plays important role in oral physiology. The aim of this study was to determin the association of the menstrual cycle and salivary ß-estradiol with the production of volatile sulfur compounds (VSC).METHODS: In this cross-sectional study, twenty female dental students in good oral and general health were recruited for evaluation of VSC, sali...