A bibliometric analysis of proton exchange membrane fuel cells (PEMFCs) content from a total of 15.020 research publications was conducted between 2008 and 2018, the papers being detailed in the online version of SCI-Expanded, Thomson Reuters Web of Science. Data processing tools such as Hitscite, CiteSpace, ArcGIS and Ucinet 6 were used to process the information. The parameters analyzed in the analysis were: type of document; the language of publication; volume and characteristics of publication output; publication by journals; performance of countries and research institutions; research trends and visibility. The study showed that "Fuel'', "Cell", "Membrane “and "Proton" were found in most of the titles of the documents, while "Performance", "Pemfc”, "Pem Fuel Cell" and "Fuel Cell" were the keywords most commonly used in documents. The analysis found that PEMFC studies have tended to be growing and that leading peer-reviewed journals have produced numerous publications on the subject. The investigation revealed that the country with the most significant production in the field is USA with a contribution of 3009; 20% of the total publications. Followed by China 2480; 16.5%, South Korea 1273; 8.5% and Germany 1121; 7.5%, showing to the main world powers as the most significant contributors to the research.

Introduction− Power converters are used in microgrids to transfer power to the load with a regulated voltage. However, the DC-AC converters present distortions in the waveform that can be improved with the help of real-time controllers. Objective− Evaluate the response in alternating current of the buck converter controlled with the ZAD-FPIC technique. Methodology− Based on the differential equations that describe the buck power converter, the ZAD and FPIC controllers are designed. Afterwards, simulations of the complete controlled system are made using Simulink of MATLAB. Then, the system is implemented experimentally and the controller is executed in real-time with the help of a DS1104 from dSPACE. In the end, several tests are carried out to check the effectiveness of the controller. Results− The results show that the controller allows good stability against different variations in the system and in the load. Conclusions− The ZAD-FPIC technique controls the variable and tracks changes in the waveform, magnitude, and frequency of the reference signal. The controller presents good stability to different tests, tracking the reference signal after each event. Keywords− Control of power converters, ZAD-FPIC technique, DC-AC converter, signal tracking Resumen Introducción− Los convertidores de potencia son utilizados en las micro redes para transferir la potencia a la carga con una tensión regulada. Sin embargo, los convertidores DC-AC presentan distorsiones en la forma de onda que pueden ser mejoradas con la ayuda de controladores en tiempo real. Objetivo− Evaluar la respuesta en corriente alterna del convertidor buck controlado con la técnica ZAD-FPIC. Metodología− Se parte de las ecuaciones diferenciales que describen el convertidor de potencia buck, luego se diseñan los controladores ZAD y FPIC, se hacen simulaciones del sistema completo controlado en Simulink de Matlab, se implementa el sistema de forma experimental y el controlador se ejecuta en tiempo real con la ayuda de una DS1104 de la empresa dSPACE, al final se realizan varias pruebas para comprobar la efectividad del controlador. Resultados− Los resultados muestran que el controlador permite que una buena estabilidad contra diversas variaciones en el sistema y en la carga. Conclusiones− La técnica ZAD-FPIC controla la variable y realiza seguimiento ante cambios en la forma de onda, magnitud y frecuencia de la señal de referencia. El controlador presenta buena estabilidad ante diferentes pruebas, siguiendo la señal de referencia después de cada evento. Palabras clave− Control de convertidores de potencia, técnica ZAD-FPIC, convertidor DC-AC, seguimiento de señales Performance evaluation of a DC-AC inverter controlled with ZAD-FPIC Evaluación del desempeño de un inversor DC-AC controlado con ZAD-FPIC

This paper discusses energy management in the formation process of lead acid batteries. Battery production and electricity consumption in during battery formation in a battery plant was analyzed over a 4 year period. The main parameters affecting the energy performance of battery production were identified and different actions to improve it were proposed. Furthermore, an Energy Performance Indicator (EnPI), based on the electricity consumption of battery formation (a difficult and rather expensive parameter to measure), is introduced to assess its energy efficiency. Therefore, a Soft Sensor to measure the electricity consumption in real-time (based on the voltage and current measured during battery formation), and to calculate the EnPI is developed. Moreover, Energy Management (EM), aided by the use of energy baselines and control charts is implemented to assess the energy performance of battery formation, allowing the implementation of rapid corrective actions toward higher efficiency standards. This resulted on the average in a 4.3% reduction of the electricity consumption in battery formation.

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