Tugce Demirdelen

Simulation modelling and analysis of modular cascaded multilevel converter based shunt hybrid active power filter for large scale photovoltaic system interconnection

Abstract Modular multilevel inverters are promising candidates for next generation of efficient, robust and reliable inverters in large scale photovoltaic system. A modular cascaded multilevel inverter based shunt hybrid active power filter (SHAPF) for three phase grid-connected large scale PV systems is represented in this paper. The main contribution of this paper is to model and control of grid interfaced large scale photovoltaic system with embedded hybrid active power filter functions. In proposed system, the features of hybrid active power filter have been amalgamated in the control circuit of the voltage controlled voltage source inverter interfacing the photovoltaic system to the grid. As a result, the same inverter part of SHAPF is utilized to inject power generated from photovoltaic source to the grid and also to act as hybrid active power filter to compensate harmonics and reactive power demand. With using compensation ability, the grid currents are sinusoidal and in phase with grid voltages. The whole system is modeled in PSCAD/EMTDC. The simulation results are demonstrated to verify the operation and the control system of the proposed system.

A New Control Approach for Shunt Hybrid Active Power Filter to Compensate Harmonics and Dynamic Reactive Power with Grid Interconnection

The grid interconnection of renewable energy source is a popular issue in the electric utilities. Different types of converter topology in grid interconnection have been improved by researchers to improve power quality and efficiency of the electrical system. The main contribution of this paper is that shunt hybrid active power filter (SHAPF) with a DC-DC converter at dc link is to provide interconnection between renewable source and grid with linear dynamic loads. The other contribution of this paper is to present a novel control strategy for reactive power compensation and harmonics elimination in industrial networks using a hybrid active power filter as a combination of a three phase, two level voltage source converter connected in parallel with single tuned LC passive filter. In proposed control method, reactive power compensation is achieved successfully with perceptible amount. Besides, the performance results of harmonic compensation are satisfactory. Theoretical analyses and simulation results are obtained from an actual industrial network model in PSCAD. The simulation results are presented for proposed system in order to demonstrate that the harmonic compensation performance meets the IEEE-519 standard.

A novel fuzzy logic control for bidirectional DC-DC converter and comparison with dual phase-shift control method in medium voltage applications

In this study, operation, design and comparison of Dual Phase-Shift and Novel Fuzzy Logic control methods on isolated bidirectional DC-DC converter are discussed. The major components (DC link capacitors and inductors) are created for dual phase shifting method in order to obtain maximum efficiency. Triggering signals, voltage-current waveforms are compared and efficiencies are listed for all of these control methods at buck and boost modes of the full-bridge converter topology without using snubber capacitors to reduce cost feasibility. The main contribution of this paper, applying one of the most common used phase-shift control method, dual phase-shift and comparing with proposed novel Fuzzy Logic control method (Fuzzy-PSO-PI) on efficiency way for medium voltage applications. In this paper, isolated bidirectional DC-DC converter topology is modelled and control algorithms are written by FORTRAN programming language.

The Analysis and Performance Results of Bidirectional DC-DC Converter Based Dynamic Voltage Restorer under Voltage Sag/Swell Conditions

This paper presents Dynamic Voltage Restorer (DVR) based on bidirectional full-bridge dc-dc converter to compensate severe voltage sag/swell problems in medium voltage system. Voltage swell causes the continuous rise at dc-link voltage of DVR which may damage the dc-link capacitors and solid-state devices, and increase the power losses. Unidirectional dc-dc converters based DVRs do not allow power flow from dc link of inverter to battery. This condition may damage the dc-link capacitors and solid-state devices, and increase the power losses. The main contribution of this study is that bidirectional dc-dc converter permits the DVR to prevent voltage rise at DC link capacitor under severe voltage swell conditions. In this topology, power can flow both from battery to multilevel inverter and vice versa. For this propose, a control algorithm based on Proportional-Integrator (PI) control is developed for bidirectional dc-dc converter. This algorithm can keep the DC link voltage constant during voltage sag/swell. The performance results of proposed topology and control method is verified with PSCAD/EMDTC.

Performance investigation of high level modular multilevel inverter based shunt hybrid active power filter

The multilevel inverters have become popular equipment for medium and high power applications in recent years. These inverters can constitute high voltage and decrease harmonics by their own circuit topologies. This paper presents a modular multilevel inverters based SHAPF for medium voltage applications, focusing on its control method and operating performance. The compensation process is based on synchronous reference frame method. Theoretical analyses and simulation results are obtained from an actual industrial network model in PSCAD. The simulation results are presented for a proposed system in order to demonstrate that the harmonic compensation performance meets the IEEE-519 standard.

PSO-PI Based DC Link Voltage Control Technique for Shunt Hybrid Active Power Filter

In power systems, the intensive use of nonlinear loads causes several power quality problems such as current harmonic pollution. In order to reduce the current harmonic pollution, the shunt hybrid active filter (SHAPF) is the best solutions effectively. In shunt hybrid active filter systems SHAPFs, the design of dc link controller is a significant and challenging task due to its impact on the performance and stability of the overall system. The main contribution of this paper is that the particle swarm optimization (PSO) algorithm is applied gains for PI controller which can result in the improved response in terms of response time and overshoot. In proposed control method, the performance results of harmonic compensation are satisfactory. Theoretical analyses and simulation results are obtained from an actual industrial network model in PSCAD. The simulation results are presented for proposed system in order to demonstrate that the harmonic compensation performance meets the IEEE-519 standard.

Adaptive Input Voltage Prediction Method Based on ANN for Bidirectional DC-DC Converter

For industrial applications, Bidirectional DC-DC converters (BDCs) are used in recent years. And also their efficiency results are improved to apply different control methods. ANN algorithms is one of the new control topic in literature. This paper attempts to improve the dynamic performance of bidirectional dc-dc converter. And it deals with a novel control scheme related with an adaptive input voltage control by using ANN algorithms based on SOM. Firstly, adaptive input voltages are classified by ANN algorithms (SOM, SVM, FF) and the best suitable and proposed ANN algorithm is SOM which is selected for this controller. The best efficiency case is selected in this algorithm. Then, the voltage values are predicted. This voltage values are used in simulation models. Thus, the proposed system works both effective and high efficiency. Theoretical analysis and simulation results obtained from an actual industrial network model in PSCAD verify the viability and effectiveness of the proposed Bidirectional DC-DC Converter (BDC).

A Novel Control Scheme for Dynamic Reactive Power Compensation Multilevel Inverter Based Shunt Hybrid Active Power Filter

This paper presents a novel control scheme for seven levels diode clamped multilevel inverter (DCMLI) topology based shunt hybrid active power filter which can compensate both dynamic reactive power and current harmonics in three phase three wire medium voltage distribution power systems as against many literatures that compensate fixed reactive power. It is on account of this novel control method, it can obtain better compensating performances compared with conventional fixed reactive power and harmonic compensation control. Dynamic reactive power compensation is supplied both active and passive filter parts of SHAPF with fixed dc link voltage. And also control algorithm for proposed SHAPF has shown its feasibility in suppressing harmonics produced by nonlinear loads. Theoretical analyses and simulation results are obtained from an actual industrial network model in PSCAD. The simulation results are demonstrated that harmonic compensation performance meets the IEEE-519 standard.

A Power Rating and Application Survey of Magnetically Controlled Shunt Reactor

MCSR can simplify the system reactive power and voltage control in the super / special high-voltage power grid, suppress power frequency and operation over voltage, eliminating generator self excitation, dynamically compensate charging the power in a transmission line, suppress the secondary arc current, damping system resonance and so on, which can meet the various needs of the system, it has a very broad application prospects. This paper presents a power rating and application survey of MCSR. It is aimed at providing a broad perspective on the status of MCSR technology to the researchers and the application engineers dealing with power quality issues. A list of more than 45 research publications on the subject is also appended for a quick reference.

A novel low cost sag/swell generator

This study presents a new Sag Swell Generator (SSG) topology to generate several power quality problems such as sag, swell and interruption. In this paper, bridge type bidirectional switch based SSG is presented to generate different fault conditions. The main contribution of proposed topology is to provide low-cost and simple solution compared to conventional transformer based SSG topologies. The experimental results show that the proposed SSG is a novel topology for low-cost laboratory applications.