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AC-DC converters are mostly used as power supplies for microelectronic systems, battery chargers, wind energy applications, electric appliances in household and dc motor drives. Switched-capacitor (SC) network based converters can be good solution to the challenges of 21st century having high voltage conversion ratio and low EMI emissions. The application of this type of converters is in microprocessor...
This paper proposes a modular multilevel converter (MMC) topology, designed particularly for load balancing in 50 Hz railway applications. The asymmetrical character of the traction load requires higher device rating for a Double-star or Delta-connected MMC compared to a symmetrical static compensator. This is due to the symmetrizing components to rebalance the capacitor voltages in the submodules...
In this work an ac-dc-ac multilevel power converter is investigated. The developed configuration is composed of one single-phase ac-dc-ac three-leg module and two H-bridges, one of them connected in the shared part of the system to employ multilevel voltages to input and output converter, and the other one connected on the grid side for input overvoltage. The converter is employed in applications...
In this paper reactive power compensation using an infinite level inverter based STATCOM is proposed. Nowadays, the society is becoming increasingly dependent on the electrical supply. New equipment's are more sensitive to power quality variations. This causes the transmission line to transfer equal or sometimes more than its capacity, which leads to overloading, voltage fluctuations etc. in the system...
Two-phase residential installations have become very common in Ecuador since different policies prompt the users to replace gas stoves and water heaters by electric appliances. The addition of a second phase to the originally installed single-phase wiring is required to obtain 220Vrms. This fact carries an intrinsic unbalance since single- and two-phase loads coexist. In this paper a topology for...
A single phase transformer-less inverter is introduced in this paper. The negative polarities of the input voltage and output terminal have common ground. Therefore, the leakage current problem that is common in PV systems is eliminated naturally. In addition, the proposed inverter has fewer components compared with its counterparts and only one switch conducts during the active states which enhance...
This paper proposes a self-tuning model predictive direct power control (MPDPC) strategy for power flow control and power quality improvement in grid-connected power converters. At each sampling instant, a fuzzy logic controller is used to determine online the best weighting factor values for a given operating point. These values are then used to solve the multi-objective optimal control problem associated...
In order to simulate the varied kinds of current and meet the acquirement on the different power, this paper proposes a multifunctional DC electronic load. The proposed DC electronic load is composed of many cascaded current simulation units. The number of units is according to the input power rating. Each unit is based on the combination of buck and boost converter, which is able to simulate both...
Performance of multilevel inverters (MLI) are distinguished because of their low harmonic waveform generation, low filtering requirements on AC side and high voltage application. Among different (MLI) topologies, cascaded multi-level inverters (CMLI) are easier to implement and are much more cost effective. The main drawback of multilevel inverters is requirement of more than one isolated DC source...
An HVDC system based on a Cockcroft-Walton (CW-HVDC) topology is presented and a novel strategy is proposed to analyze and control the converter. In the connection to the grid the CW-HVDC uses a 3×2 matrix converter. The CW-HVDC voltage state-space vectors are derived and used to control the AC currents, guaranteeing nearly unitary power factor in the connection to the grid. Sliding mode controllers...
A study assessing a wind farm's reactive power compensation system topology and the impact of priority of utilizing each component part thereof on electrical losses is presented here; the estimated losses were assessed over a period of 25 years at a typical onshore wind farm in the UK. STATCOM based hybrid solutions not only offer benefits of reduced initial CAPEX but they also offer substantial electrical...
This paper presents a single phase converter topology that integrates a second harmonic energy buffer. The buffer is formed by converting one branch of the converter to use half-bridge cells, similar to an MMC type design. The energy buffer allows complete elimination of the 2nd harmonic ripple from the main DC bus and reduces overall DC link capacitor size. The topology also reduces the rms current...
The offline SMPS are efficient, lightweight widely used converters in consumer electronics connected to utility mains. Because of high-frequency switching, they produce conducted and radiated EMI also offering low power factor to the utility mains. The two issues involved in the SMPS are to increase the Power Factor and to mitigate the EMI, to comply with EMC standards. Techniques for reducing the...
This paper starts with the basics of contactless energy transfer systems for charging of electric vehicles and discusses reactive power compensation networks for single-phase and three-phase systems. After presenting a small scale model of a three-phase prototype with distributed windings, results from measurements and simulations will be described for further investigations.
This paper presents a novel single-stage non isolated switched capacitor based AC-DC converter for power factor correction (PFC). This converter features single switch, transformer less high voltage gain, and improves the power factor, reduces THD and voltage stress across the switch. Average current mode controller has been used to achieve PFC. In this paper proposed converter topology, its principle...
This work addresses a single-stage active power factor correction (PFC) scheme that is implemented using a Floating Interleaved Boost Converter (FIBC) equipped with an indirect Double Integral Sliding Mode Controller (DISMC) adopted for a single phase full bridge rectifier. Due to the high gain, high efficiency and small size components, FIBC-based approach can achieve unit power factor and voltage-regulation...
Single stage converter system (SSCS) does both dc-dc conversion and dc-ac conversion in one stage. In this paper, a SSCS for photovoltaic (PV) applications is presented. This system can deliver active power from PV to the grid while continuously tracking maximum power point (MPP). The proposed system is controlled such that it can deliver/receive reactive power from grid. The presented system has...
In conventional photovoltaic microinverters configuration, a single PV module is connected to the grid through two converter stages: a step-up dc-dc stage and a step-down dc-ac stage. In the first stage, a high frequency transformer is generally used to achieve the high step-up voltage ratio conversion to a voltage above the grid peak value, reducing the converter efficiency while increasing its size...
A novel three-phase multilevel inverter using a single dc source is proposed in this paper, which uses flying capacitors for generating different voltage levels. Pole voltage levels can be of five levels or higher than that. The structural similarity of the front end of the proposed inverter with that of the three-level neutral-point clamped inverter and the presence of redundant switching states...
DC power conditioning and processing is an essential challenge now a days. Rectifiers having bridge structures are considered to be nonlinear as they draw non sinusoidal current from line. This distorted current causes several problems related to power quality. In this paper, a new configuration of single phase single switch controlled rectifier using SEPIC topology is proposed. The input current...
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