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A model predictive control system for delta-connected modular multilevel converter is proposed in this paper. The control system is based on offline computed optimal pulse patterns, which are modified online using model predictive control. Optimized pulse patterns facilitate the shaping of the grid current spectrum at low switching frequencies. Unlike conventional control methods with optimal pulse...
This paper proposes the modeling of single phase symmetric flying capacitor multilevel inverter (SFC-MLI) for Static synchronous compensator (STATCOM) application. The proposed topology is composed of cascade-connected five-level SFC modules. The linear current controller with phase shifted and phase disposition pulse-width modulation (PS-PD-PWM) base switching technique has been implemented. To takes...
A comparative analysis of efficiency of the time-delayed feedback for nonlinear dynamics control of composite power converters is carried out. In each case, the method efficiency is estimated both by the area of the desired dynamic mode in the space of two system parameters and by the critical value of the proportional controller gain. Dynamic modes maps are given for each type of a composite converter...
The fuel cell systems are considered as current intensive sources with low output voltage, so power electronic converters are essential part of fuel cell applications. A dc/dc converter with high voltage ratio and low stress is developed in this paper. The inductors of the output series interleaved boost converter (OS-IBC) are interleaved in parallel at input which can reduce the input current ripple...
The paper aims to analyze and improve stability profile of transmission system of Makran area of Baluchistan, Pakistan, with help of different reactive power compensating devices. To maintain the flow of active power in a power system, adequate supply of reactive power is essential; maintenance of voltage stability confirms this reactive supply. Whenever the system fails to meet its voltage demand...
This paper presents the capacitor size reduction of a MMC-based transformer-less STATCOM for medium voltage ac distribution system. The instantaneous power swinging flows into the single-phase configuration results in a high capacitance needed; however, by accepting the swinging voltage in the capacitor, the capacitance can be drastically reduced. This paper analyzes the dimensional size reduction...
In this paper, a Selective Harmonic Elimination Pulse Width Modulation (SHE-PWM) method, which utilizes adjustable dc links, is presented for a Static Synchronous Compensator (STATCOM) based on Cascaded H-Bridge (CHB) multilevel converter. The proposed switching algorithm is able to fix the capacitors voltages at optimum and unequal values, while injecting the desired reactive power, in order to eliminate...
This paper addresses the modular multilevel converter applied as a static synchronous compensator. The main objective of this work is to compare the converter performance considering two different submodule capacitor voltage balancing strategies: nearest level control and phase-shifted pulse width modulation, during positive and negative sequence current injection. Results of a 15 MVA MMC STATCOM...
In this paper, a single-stage power-factor-correction (PFC) rectifier with active power decoupling function is proposed. The proposed rectifier has a low component count as compared to existing solutions. Only two active switches, one inductor and one small power-buffering capacitor are needed. High power factor, wide output voltage range and active power decoupling can be simultaneously obtained...
A real-time simulation for the Cascaded STATCOM fully implemented on field-programmable-gate-arrays (FPGA) is proposed in this paper. The switching-function model for the STATCOM is employed, where the IGBTs and diodes are taken as ideal switches, to reduce the amount of calculation. With the help of external circuit calculation, the operation in dead-time period is taken into consideration, which...
This paper proposes a fuzzy PI based voltage control scheme of the self-excited induction generator (SEIG) using static synchronous compensator (STATCOM) for feeding balanced and unbalanced load. The main aim of SEIG discussed in this paper is to regulate voltage under balanced and unbalanced load conditions. A three-phase insulated gate-bipolar-transistor based current controlled voltage source inverter...
Grid-connected solar photovoltaic (PV) system significantly contributes to worldwide renewable energy growth and penetration, specifically the integration of PV system into the grid has become an important issue in the last decade because of the huge expansion of new power plants. Modular multilevel converter (MMC) is an upcoming promising converter technology for medium-/high-voltage applications,...
This study deals with the stabilization of grid connected wind farms. Operation of wind turbines has an impact on the power quality and reliability at the connected electric network. Power quality problems such as voltage flicker and harmonic distortion along with reliability issues are some major concern and in this work the flicker & harmonics issues are considered. Wind turbine connected to...
This paper presents a simulation study for a built prototype of modular multi-level flying capacitor cascade converter as a STATCOM. The converter modulation scheme applied is based on Phase Shifted PWM and the two scenarios which require compensation are investigated to verify this topology. The two scenarios are PCC voltage regulation and unity power factor correction through reactive power compensation...
Cascaded H-bridge (CHB) converter is one of the popular solution for medium voltage transformerless static synchronous compensator (STATCOM) applications. The semiconductor devices of this converter are switched at low frequency. Therefore, conduction losses contribute to major part of the losses in this converter. To reduce the conduction losses, a cascaded U-cell (CUC) multilevel converter is derived...
In this paper, five-level Static Synchronous Compensator (STATCOM) is analyzed with reduced number of power switches. The simulation has been performed by using a digital signal processing unit (DSP) and Matlab/Simulink together. Selective harmonic elimination, single phase real (P) and reactive (Q) power methods are used to control power flow in the delta connected converter. The response of STATCOM...
For an AC/DC coupled transmission system, the change of transmission power on the DC lines will significantly influence the AC systems' voltage. This paper describes a method to coordinated control the reactive power of power plants and shunt capacitors at DC converter stations nearby, in order to keep the voltage of the pilot bus tracking its set point considering the DC system's transmission schedule...
STATCOM utilization to compensate the reactive power of the grid must be protected from faults in the switches. The switching of the STATCOM makes it more vulnerable to switch failures such as open circuit and short circuit due to high frequency switching. This paper introduces several switching techniques applied to a 13-level cascaded H-bridge inverter topology with fault detection and mitigation...
This paper presents a voltage control scheme for coordinating reactive power reserves, inspired by the concept of multi-agent system. Similar to an agent, the proposed controller takes on assigned tasks itself and contacts neighbors for support when needed. The control structure incorporates not only controllable VAr sources but also switched capacitor banks, resulting in increased online reactive...
We consider joint control of a switchable capacitor and a D-STATCOM for voltage regulation in a distribution circuit with intermittent load. The control problem is formulated as a two-timescale optimal power flow problem with chance constraints, which minimizes power loss while limiting the probability of voltage violations due to fast changes in load. The control problem forms the basis of an optimization...
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