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This paper presents the design and optimization of an isolated DC-DC converter that could be potentially selected for advanced multilevel topologies for offshore wind turbine applications. The superior properties of Silicon Carbide material in terms of switching speed, voltage withstand and efficiency provides the possibility to develop a highly optimized DC-DC converter.
This paper describes selected issues concerning realization of energy storage system (ESS) designed to operate in power distribution system. This paper presents a modular approach of 300 kVA power converter operating with superconducting magnetic energy storage (SMES), which gives high dynamics together with high power and suitable capability for instantaneous energy storage. Analysis and simulation...
The application of Gallium Nitride (GaN) power transistors in a single phase inverter for photovoltaic (PV) systems is presented inverter. The power of the system is 2 kW. For both stages (DC boost stage and inverter stage), a very high switching frequency of 250 kHz is used. By this, a highly compact design for the inverter (200 × 150 × 80 mm3 / 2.4 l) was reached. The power to weight ratio corresponds...
An improved modulation algorithm is proposed for three-phase face-to-face topology. The algorithm could make the face-to-face dc transformer use 1: 1 ac transformer or omit ac transformer in a wide variable ratio range to reducing the volume of the system. The simulation in MATLAB/Simulink validates the proposed algorithm.
A modular-multilevel (MMC) DC/DC converter is proposed in this paper, which can be deployed to inter-connect DC grid of different voltage levels, especially in the new energy sources such as wind power and solar power grid connection. Its key features include: 1) step-up and step-down operation. 2) bidirectional power flowing. 3) bi-directional fault blocking similar to a DC breaker. The operation...
This paper shows that the ZETA-SEPIC converter can be used as a bidirectional charging system between a high DC link voltage and a low voltage battery system. Main advantages are transformerless operation and that the coupling capacitor protects and separates both sides of the converter in case of short circuits.
Microinverters connect a single photovoltaic (PV) module to the grid, and therefore require a high voltage step-up conversion ratio. This is usually achieved in a two-stage approach with a step-up dc-dc converter followed by a step-down inverter. More recently single-stage step-up inverters have been proposed under the assumption that less stages improves efficiency. This paper compares these two...
This paper proposes a three-phase six-inductor double-switch PFC circuit which is suitable for high frequency UPS application. This PFC circuit not only achieves high power factor correction in grid-connected mode of UPS, but also improves bus voltage in battery mode of UPS. This new PFC removes the independent boost design in common UPS and the whole cost can be reduced. The topology structure and...
A novel topology for LED drivers is proposed. The system does not require rectifier input stage nor storage DC bus capacitor. The topology is described and studied by simulation. Experimental results on an AC LED demonstrator using GaN transistors validate the proposed circuit.
The current energy constraints are pushing researchers to design and optimize power electronic devices for integrating and consuming renewable energy more efficiently. In this paper, a voltage sensorless Model Predictive Control (MPC) solution is proposed for the grid integration of a Packed U Cells (PUC) based PV system. The studied topology is a grid-connected 4-cell 15-level PUC inverter. The control...
This paper compares several multilevel topologies (3L-NPC, 3L-TNPC, 5L-ANPC and 5L-SMC converters) as an alternative to the 2L converter for low voltage applications, using low voltage IGBT modules. The comparative evaluations are made considering figures of merit such as the total losses and their power loss distribution, the amount of devices of each converter, the maximum output power, the harmonic...
This paper describes a transformerless STATCOM (Static synchronous compensator) based on the MMCC-SDBC (modular multilevel cascade converter — single-delta bridge-cells) for independent control of positive- and negative-sequence reactive powers. A three-phase 200-V 6-kVA experimental system is designed, constructed and tested to verify the effectiveness of the topology and the control method including...
In this paper, a novel bridgeless Flyback power factor correction rectifier is presented. Two active power switches, rather than the line-voltage diode bridge, are used to provide the bidirectional power flow. In comparison with the existing Flyback rectifiers, the proposed topology uses less number of transformer windings which simplifies the complexity of implementation in terms of magnetic utilization...
In this manuscript a new interleaved topology based on the three-port boost converter is presented. A new modulation scheme that works for the interleaved and non-interleaved 3-port boost converters is proposed as well. Models for interleaved and non-interleaved converters that describe the behavior in any of the different working modes are developed. These models can be easily averaged in order to...
A transformerless multicellular dc-dc converter has been newly proposed. The capacitively isolated dc-dc cell converters have been applied to develop the multicellular converter without using high frequency transformers. The high voltage transformation ratio is achieved by the ISOP (Input Series Output Parallel) connection topology of the cell converters and the realization of the highly efficient...
Modular Multilevel Converter (MMC) has served as a promising Voltage Source Converter (VSC) for High Voltage Direct Current (HVDC) applications. In this paper, a new MMC Submodule (SM) topology called Modified Switched Capacitor Sub-Module (MSCSM) is proposed. The MSCSM is able to block the DC fault using the power electronics semiconductor diodes due to its intelligent configuration without the need...
In modern traction drives the transformer causes a high amount of the overall losses. A transformer with lower losses however increases the THD of the output current and the amplitude of the fault current. Two converters will be presented which make the utilization of an enhanced transformer possible.
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...
Supplying 25 kV, 50 Hz railway systems is a challenging task due to the load characteristics of those systems. Hence, several approaches are developed to improve their grid integration with the static frequency converter based substations. However, this supply system can be further refined by the application of a dc grid. Hence, this paper presents and discusses one possible approach to enhance the...
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...
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