E. Arango

Maximum power point tracking in wind farms by means of a multivariable algorithm

A maximum power point tracking strategy based on a multivariable perturb and observe algorithm aimed at maximizes the power generated in wind farms, reducing the requirements in terms of current sensors and control units is presented in this paper. Such a solution increases the economical viability of wind power systems, since the same power is extracted in comparison with classical wind farms, but a reduced number of components are required. Comparison of the power extracted from a generalized wind farm using the algorithm proposed vs a traditional MPPT algorithm is presented. Simulation results confirm that the proposed solution extracts the maximum power but only using one current sensor and one control unit.

Automatic Parameters Calculation of Controllers for Photovoltaic dc/dc Converters

In the photovoltaic (PV) systems, the main objective of the control strategy is to extract the maximum power from the source; usually such objective is obtained by combining the action of the MPPT algorithm with a voltage regulator used to attenuate the disturbances at the source terminals. This work proposes an automatic procedure for designing the parameters of the voltage compensation network by solving a set of two nonlinear equations in which, the system phase and gain margins are previously assigned. The method is based on the modeling of the complete PV system (source, converter and load) and takes into account the main parasitic components also. Thanks to this global approach, the design of control strategies to regulate the PV panel output voltage can be optimized. The method has been theoretically analyzed and validated by using PSIM simulations. The designed voltage control loop has been tested also together with a P&O MPPT algorithm in order to regulate the PV voltage in a double stage grid-connected inverter in presence of a wide voltage oscillation at the DC-bulk and with fast irradiance variation.

Fuel Cell Power Output Using a LQR Controlled AIDB Converter

A fuel cell power output system is presented. The output voltage and current of a fuel cell are the sources of a new DC/DC converter topology, the asymmetrical interleaved dual boost converter - AIDB. This converter inherently operates in discontinuous conduction mode (DCM), which provides characteristics of applicability with a fuel cell, but also due to the DCM mode, a new outline for getting the model is necessary to apply. Then the model is used for designing a LQR control that is verified by simulation. The proper operation of the whole fuel cell power output system is demonstrated by simulation in Matlab using mathematical models of a fuel cell and the controlled converter.

Digital controllers design analysis for DC/DC converters in PV applications

The development on photovoltaic (PV) applications along with recent breakthroughs in power electronics and processors technologies, has became in a strong research area especially in modeling and control techniques, for which digital controllers offer some advantages over analog controllers; however their design does not always lead to accurate performances. This paper proposes to adopt an analog design of digital parameters, which provides the digital controller parameters to ensure a correct operation of the maximum power point tracking (MPPT) algoritmth, fulfilling analog design ensuring system stability, low cost and implementation complexity.

Grid-connected photovoltaic system featuring low-frequency ripple suppression and high voltage conversion ratio

A grid-connected photovoltaic system, based on a sixth-order dc/dc converter with a non-linear compensation technique, is proposed. This solution addresses the main challenges in double-stage photovoltaic systems connected to the grid: increase the dc/dc stage voltage conversion ratio, reduce the photovoltaic voltage ripple, avoid electrolytic capacitances, and mitigate the effect of dc-link voltage oscillations generated by grid-connected inverters. The compensation technique is analytically derived from the voltage conversion ratio of the dc/dc converter, therefore its design does not require a control-oriented model, and the compensator is independent from the system parameters, which simplify its application. Finally, the proposed solution is validated by means of detailed PSIM simulations.

DESIGN OF A LOW POWER SYSTEM BASED ON FUEL CELLS (DISEÑO DE UN SISTEMA DE BAJA POTENCIA BASADO EN CELDAS DE COMBUSTIBLE)

The design of a low power system based on a fuel cell and the series interconnection topology is proposed in this paper. The detailed design of the power electronics devices, the small signal and dynamic modeling of the system, and the associated control structures specification, design, and analysis are presented. The converters are designed to protect the fuel cell from current harmonics and high frequency transients, and to provide regulated voltage to the load, which could exhibits both steady state and transient current profiles. The proposed design procedure is applicable to any power system based on fuel cells, and it is illustrated with an experimental H-30 fuel cell prototype, providing satisfactory detailed PSIM simulation and experimental results that validate the paper contributions. Resumen: Este articulo presenta el diseno de un sistema de baja potencia basado en pilas de combustible y la topologia de interconexion en serie. El articulo incluye el diseno detallado de los dispositivos de electronica de potencia, el modelado dinamico y de pequena senal del sistema y la especificacion, diseno y analisis de las estructuras de control de los convertidores, que son disenados para proteger la pila de combustible de los armonicos de corriente y los transitorios de alta frecuencia, ademas para garantizar un voltaje regulado en la carga, el cual puede exhibir perfiles de corriente de estado estable y transitorios. El diseno propuesto es aplicable a cualquier sistema de potencia basado en pilas de combustible y es ilustrado con la pila de combustible H-30, que muestra resultados satisfactorios en un ambiente de simulacion con el software PSIM y en el prototipo experimental, los cuales validan las contribuciones del articulo.