A simulation study between the DQO gate firing unit (GFU) and a proposed GFU for high voltage direct current (HVDC) rectifier based on the CIGRE benchmark model in Matlab/Simulink is carried out. The proposed GFU does not use traditional phase lock loop (PLL) and offers structural simplicity, fast response and immunity to ac system voltage unbalance, harmonics, voltage sag, frequency jump and p...

For medium voltage, high power applications 3-phase neutral point clamped AC-DC multilevel converters are becoming a good choice. In this paper the performance of a 3-phase neutral point clamped Active Front End three level converter for high power application with simplified control scheme is presented. A complete mathematical model of the control scheme is developed and performance is investi...

A serious constraint in multilevel inverters is the capacitor voltage-balancing problem. The unbalance of the different DC voltage sources of the five-level Neutral Point Clamping Voltage Source Inverter (NPC-VSI) constituted the major limitation for the use of this power converter. To remedy to this problem, a new control solution to compensate the unbalanced DC voltages for the five-level NPC...

With the large-scale construction of high-speed railway and wind farms, traction power supply system (TPSS) farms are connected through system. The three-phase unbalance grid voltage caused by TPSS will seriously affect traditional farms’ operation control. Considering to system's public point common coupling (PCC), farm's current control support strategy studied. Firstly, aiming suppress influ...

While the unified power quality conditioner based on modular multilevel converter (MMC-UPQC) can be used for recovering of voltage and current in high grids, it is difficult to manage when grid imbalance large. In this paper, a passivity-based control (PBC) combined with sliding mode (SMC) proposed MMC-UPQC improve under unbalance systems. First, according structure MMC-UPQC, equivalent mathema...