Voltage source converters (VSCs) are highly vulnerable to DC fault current; thus, protection is one of the most important concerns associated with the implementation of multi-terminal VSC-based DC networks. This paper proposes a protection strategy for medium voltage DC (MVDC) distribution systems. The strategy consists of a communication-assisted fault location method and a fault isolation sch...

In this paper, a global stability and robust nonlinear controller for VSC-HVDC transmission Converters applying input-output linearization (IOL) techniques is proposed. The feedback linearization based nonlinear differential-geometric techniques is used to cancel nonlinearities and decouple the input control variables. Global tracking capability with zero steady-state error of the voltage loop ...

This paper presents the analyzed results of using a high-voltage directcurrent (HVDC) link based on voltage-source converter (VSC) to achieve damping improvement of four parallel-operated doubly-fed induction generator (DFIG)-based offshore wind farms (OWFs) fed to a large power grid. A frequency-domain scheme based on eigenvalue analysis is carried out and a time-domain method based on nonline...

Resonances can have negative impact on a Voltage Source Converter-High Voltage DC (VSC-HVDC) system. This paper develops dc impedance models for the rectifier and inverter stations for a VSC-HVDC system when they are viewed from a dc terminal. The impedance models take converter controllers into account. The derived impedance models are validated by comparing frequency responses of the analytic...

This paper focuses on a second order sliding mode based direct power controller (SOSM-DPC) of a three-phase grid-connected voltage source converter (VSC). The proposed control scheme combined with fuzzy logic aims at regulating the DC-link voltage of the converter and precisely tracking arbitrary power references, in order to easily control the system’s power factor. Therefore measures are prop...

Fuzzy adaptive sliding mode control method is a good way to resolve the control problem when the system mathematic model is unknown. However, reaching condition must be satisfied in this method. In this paper, a kind of fuzzy adaptive variable structure control method is presented in which sliding mode doesn’t exist in closed-loop system. Dynamic fuzzy logical system (DFLS) is introduced to for...

In this paper three leg Voltage source converter (VSC) based Hybrid Active Power filter (HAPF) is proposed for existing problems of harmonics, reactive power compensation, high total harmonic distortion (THD) and Power factor improvement for three phase non linear loads. In the system, a hybrid active power filters which is the combination of active filter and passive filter. The reference curr...

In order to improve the performance of voltage source converter-high voltage direct current (VSC-HVDC) system, we propose an improved auto-disturbance rejection control (ADRC) method based on least squares support vector machines (LSSVM) in the rectifier side. Firstly, we deduce the high frequency transient mathematical model of VSC-HVDC system. Then we investigate the ADRC and LSSVM principles...