Informe técnico, basado en un protocolo de ensayos de laboratorio, de verificación del funcionamiento del equipo V-check MP

Postprint (published version

Parameter-independent battery control based on series and parallel impedance emulation

Appropriate voltage control is essential in order to extend the useful life of a battery. However, when universal chargers are used, the design of this control becomes more complicated, given the fact that the battery impedance value may vary considerably, depending not only on the operating point but also on the type, size and aging level of the battery. This paper firstly shows how the voltage regulation can become extremely variable or even unstable when the controller is designed according to the proposals in the literature. We then go on to propose the emulation of a series and parallel impedance with the battery, which is easy to implement and achieves a control that is completely independent of the battery connected. The simulation results obtained for batteries with resistances ranging from 10 mO to 1 O, show the problems with existing controls and confirm that the proposed control response is similar for all the possible range of battery resistances.Peer ReviewedPostprint (published version

Sliding-Mode Control Design of a Boost-Buck Switching Converter for AC Signal Generation

This paper presents a sliding-mode control design of a boost–buck switching converter for a voltage step-up dc–ac conversion without the use of any transformer. This approach combines the step-up/step-down conversion ratio capability of the converter with the robustness properties of sliding-mode control. The proposed control strategy is based on the design of two slidingcontrol laws, one ensuring the control of a full-bridge buck converter for proper dc–ac conversion, and the other one the control a boost converter for guaranteeing a global dc-to-ac voltage step-up ratio. A set of design criteria and a complete design procedure of the sliding-control laws are derived from small-signal analysis and large-signal considerations. The experimental results presented in the paper evidence both the achievement of step-up dc–ac conversion with good accuracy and robustness in front of input voltage and load perturbations, thus validating the proposed approach.Peer Reviewe

Towards an on-chip boost switching power converter: a design space exploration

This work presents the design space exploration of a boost switching power converter focused on its monolithic implementation. An analysis in terms of the models of its main circuit elements (switching transistors, inductor, and capacitor) is described. The figure of merit is defined taking into account output voltage ripple, power efficiency, and occupied die area as performance indexes, from which a singular point that maximizes performance is obtained. Transistor-level simulation results for a particular 0.35 mm standard CMOS technology are presented to validate the approach.Peer ReviewedPostprint (published version

A Fixed-Frequency Quasi-Sliding Control Algorithm: Application to Power Inverters Design by Means of FPGA Implementation

In this paper a fixed-frequency quasi-sliding control algorithm based on switching surface zero averaged dynamics (ZAD) is reported. This algorithm is applied to the design of a Buck-based inverter, and implemented in a laboratory prototype by means of a field programmable gate array (FPGA), taking into account processing speed versus computational complexity trade-off. Three control laws, namely sliding control (SC), fixed-frequency quasi-sliding ZAD and PWM-based control have been experimentally tested to highlight the features of the proposed algorithm. According to the experimental results presented in the paper, the ZAD algorithm fulfills the requirement of fixed switching frequency and exhibits similar robustness properties in the presence of perturbations to those of sliding control mode.Peer Reviewe

Electrical PV array reconfiguration strategy for energy extraction improvement in grid-connected PV systems

This paper applies a dynamical electrical array reconfiguration (EAR) strategy on the photovoltaic (PV) generator of a grid-connected PV system based on a plant-oriented configuration, in order to improve its energy production when the operating conditions of the solar panels are different. The EAR strategy is carried out by inserting a controllable switching matrix between the PV generator and the central inverter, which allows the electrical reconnection of the available PV modules. As a result, the PV system exhibits a self-capacity for real-time adaptation to the PV generator external operating conditions and improves the energy extraction of the system. Experimental results are provided to validate the proposed approach.Postprint (published version

El concepto de Smart Metering en el nuevo escenario de distribución eléctrica

La medición inteligente se ha convertido en un tema de la máxima actualidad y de importancia creciente; ya se aplica la normativa para su despliegue, se desarrollan proyectos piloto y han llegado al mercado nuevos dispositivos. En este trabajo se recogen propuestas y tendencias de los contadores actuales de energía eléctrica. El contador se representa como la interfaz entre el sistema del usuario, que es el consumidorproductor distribuido de energía, y la red eléctrica. A partir de esta relación y con la tecnología electrónica actual aparece el concepto denominado “smart metering”. El documento describe las funciones de los contadores de energía eléctrica desde el inicio, con el contador electromecánico hace 120 años, hasta los dispositivos actuales. Se incluyen las características genéricas de medida, las tecnologías de estos equipos y referencias normativas que utilizan estos sistemas de medida de energía eléctrica. Se concluye con las tendencias previsibles en un futuro inmediato.Postprint (published version

Banco de ensayos para la caracterización del rendimiento energético y del rendimiento del MPPT en convertidores fotovoltaicos

En este trabajo se presenta una propuesta de ensayo para caracterizar el comportamiento del algoritmo de seguimiento de punto de máxima potencia (MPPT: Maximum Power Point Tracking) programado en los convertidores fotovoltaicos (PV: Photo-Voltaic). Este ensayo también permite estimar el rendimiento energético de dichos convertidores. Para los ensayos propuestos se utiliza un simulador de generador fotovoltaico (SAS: Solar Array Simulator) junto con un equipo para la medida y registro de potencia instantánea. Los convertidores ensayados (DUT: Device Under Test) para verificar el banco de pruebas utilizado son: un inversor con inyección a red y un convertidor DC/DC para carga de baterías. Para la evaluación del sistema se han realizado dos tipos de ensayos, uno denominado estático, para evaluar las fluctuaciones del algoritmo MPPT alrededor del punto de máxima potencia (MPP: Maximum Power Point) del generador PV y otro ensayo, denominado dinámico, para evaluar el comportamiento del MPPT cuando se produce un cambio en el valor de los parámetros que determinan el MPP del generador PV. Finalmente se presentan los resultados obtenidos tras los ensayos realizados y se valora el comportamiento de los DUT.Postprint (published version

Power sizing factor design of central inverter PV grid-connected systems: a simulation approach.

This paper presents a simulation approach which can help in the preliminary power sizing design of a gridconnected PV system based on a single inverter configuration. Given a nominal peak power of the PV array, this simulation procedure leads to the PV inverter maximum rated power which maximizes the yearly injected energy to the grid.Peer ReviewedPostprint (published version

Bandwidth-Enhancement gm-C Filter with independent ¿o and Q Tuning Mechanisms in Both Topology and Control Loops

This paper deals with the proposal of a new topology for a gm-C continuous time filter which allows the adjustment and tuning of its characteristic parameters (ωO and Q) in an independent way (without cross-tuning), thereby extending the Q range of the filter for a particular ωO value. Additionally a comparison of three different Q-tuning algorithms is presented. It is shown that an LMS-based Q-control strategy allows to overcome the intrinsic dependence between the Q and ωO tuning loops. The combination of both the proposed filter topology and the selected control loop algorithms results in an enhanced transient performance as well as an improvement in terms of cross-detuning.Postprint (published version