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AC voltages in the range of few kV have to be processed before being fed to traction motors. DC traction motors are normally designed for medium voltage and high current (1.2kV-1.5kV and 1200-1500A). Front-End Buck-Rectifiers are a viable solution for direct conversion of high ac voltage to low dc output voltage. However several buck-rectifier modules need to be connected in input-series output-parallel...
A hybrid modeling technique in CCM (Continuous Conduction Mode) and equally valid in DCM (Discontinuous Conduction Mode) is proposed for the step-down Buck converter. An improved ν-resolution model is obtained which easily allows the deduction of the equivalent PWA (Piecewise Affine) model that is adequate for predictive control design. Simulation results of the open-loop model are presented, proving...
In this paper, implementation of a low power, low voltage AC-DC converter is presented. Unlike DC-DC converters, direct AC-DC converters generally do not have a common ground. Such a structure makes implementation of feedback and control difficult. A novel indirect feedback strategy is proposed to solve this problem. The idea is to emulate the load impedance referenced to the system ground. The feedback...
This paper presents a three-phase grid-connected photovoltaic generation system with unity power factor for any situation of solar radiation. The modelling of the PWM inverter and a control strategy using dq0 transformation are proposed. The system operates as an active filter capable of compensate harmonic components and reactive power, generated by the loads connected to the system. An input voltage...
An analytic method to evaluate frequency dependent losses in on-chip DC-DC buck converters is presented in this paper. These converters feature high switching losses caused by the skin effect in the package inductors. The frequency dependent air-core inductor model is shown to be critical in determining the optimal switching frequency. A general RLC parameter extraction method is also described. Considering...
This paper presents a simple control structure for the stand alone operation of Self Excited Induction Generator used to operate under variable loads. The proposed system uses PWM Voltage Source Inverter, DC-DC Boost Converter and diode bridge Rectifier with SEIG. The required reactive power for the Self Excited Induction Generator is supplied by means of a capacitor bank and the PWM converter to...
This paper presents the comparison between PEM fuel cell and gas turbine. THE dynamic model of PEM fuel cell and gas turbine will be described. To control of voltage and frequency, control loop added to the PEM fuel cell model. For the gas turbine speed control loop added to its model. Dynamic model are used to determine response of PEM fuel cell and gas turbine to variation load. The results are...
In this paper analysis and robust stabilizing digital controller design for a zero-voltage turn-ON boost converter (ZVTBC) is presented. The steady-state performance and zero-voltage switch-ON methodology has been analyzed and then its state-space models are formulated to obtain the small-signal models. These linearized models are then used in the design of digital voltage-mode controller. A loopgain...
In this paper analysis and design of deadbeat current control for the coupled inductor boost dc-dc converter is proposed. With the help of state-space technique, mathematical models are formulated, and then the discrete compensator designed using deadbeat control theory. Salient features of the coupled inductor topology are compared with the conventional boost topology. The compensator design is validated...
This paper introduce a new isolated bridgeless AC to DC converter with power factor correction capability. This power factor correction (PFC) circuit is capable to perform the AC to DC conversion without the diode bridge rectifier and able to obtain low output voltage which is more suitable to most applications. The detail small signal and steady state analysis of the converter operated in discontinuous...
This paper presents a current control for single phase grid connected inverters. The method allows for inverter active and reactive power control. The method uses the Direct-Quadrature (DQ) synchronous reference frame transformation for single-phase converters. This method transforms an orthogonal pair consisting of the inverter output current and a time shifted version of this current from a stationary...
Modeling and simulation generally form an integral part of design process. The simulation tools are increasingly important in the development of new system and their optimum design. This paper presents design and simple method of modeling DC-DC converter using MATLAB/Simulink. The nonlinear parameters such as equivalent series resistance of the inductor and capacitor and the threshold voltage of MOSFET...
This paper proposes a hybrid AC/DC micro-grid which consists of an AC grid and a DC grid and operates in both grid-tied and autonomous mode. Wind turbine generators (WTGs), diesel generators (DGs) and conventional AC loads are connected to the AC grid whereas photovoltaic arrays with boost converter (PVBC), fuel cell generators and DC loads are tied to the DC grid. AC bus and DC bus are coupled through...
This paper presents the modelling and simulation of proton exchange membrane (PEM) fuel cell (FC) together with a dc-dc converter and dc-ac inverter. The need for the dc-dc converter arises as a result of the output voltage generated from the FC which fluctuates with variation in load. The FC voltage is therefore, controlled using dc-dc converter to provide a regulated dc voltage output at 220 V for...
A decentralized controller for the synchronization of two remote parallel voltage source inverters used to supply train auxiliaries is presented. A modular hybrid dynamic model of the entire power electronic apparatus is constructed; possible unbalanced line and load impedances are also considered. The power sharing between the converters is obtained by designing a droop controller based on local...
This project has been oriented to the development of an energy system unit for powering tramways during shorts periods of time. The aim of this work is to present the results obtained for a high frequency DC-DC converter which is included in the energy unit. The energy unit will consist on two type of energy storage devices: a battery stack and a supercapacitor stack. A comparison of the simulated...
At present increasing power electronic converters are being applied in improving power quality. This paper adopts and realizes a detection method which can accurately extract harmonic or reactive currents under asymmetric or distorted supply voltage conditions for multi-target trend of power quality equipment. The PSCAD simulation model is built, and the method proved by high power experiment with...
This paper concentrates on the modeling and control of three-phase stand-alone photovoltaic (PV) generation system. The system is mainly composed of a solar array, dc/dc boost converter, three-phase inverter, system controller, and an output load. Sliding mode controllers are used for boost converter and three-phase inverter to achieve the maximum power output, regulated DC voltage, and the desired...
Microgrids can be defined as distribution systems with distributed generation (DG) units, energy storages and controllable loads. Microgrids are expected to form an essential part of future Smart Grids with self-healing feature. Most of the time microgrids will be operated normally parallel with utility grid. In addition to this microgrids have a special self-healing capability, because they can continue...
This paper presents a modeling of photovoltaic (PV) module in PSCAD/EMTDC and design of maximum power point tracking (MPPT) using boost converter. The model can be used for simulation studies of grid interface applications using voltage source converter in the PSCAD. The validity of the PV model developed has been verified using the set of data collected experimentally. In order to extract maximum...
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