Strategies for extracting the three-phase reference currents for shunt active power filters are compared, evaluating their performance under different source and load conditions with the new IEEE Standard 1459 power definitions. The study was applied to a three-phase four-wire system in order to include imbalance. Under balanced and sinusoidal voltages, harmonic cancellation and reactive power compensation can be attained in all the methods. However, when the voltages are distorted and/or unbalanced, the compensation capabilities are not equivalent, with some strategies unable to yield an adequate solution when the mains voltages are not ideal. Simulation and experimental results are included

Integration of renewable energy sources, active role of consumers and energy management systems are currently among research priorities in energy systems. This paper proposes an innovative coordinated energy scheduling for a microgrid of neighbor prosumers with different consumption patterns. All prosumers have photovoltaic generation systems, Li-ion batteries as energy storage systems and regular household loads. A genetic algorithm is used to schedule each prosumer's battery charge/discharge, with the aim of reducing energy exchange losses by minimizing the power in the point of interconnection of the microgrid with the main grid, with several advantages compared to classical optimization objectives, and without worsening battery lifespan degradation. Individual and coordinated strategies are compared and self-consumption and self-sufficiency of the prosumers' set are evaluated with the aim of showing the advantage of coordination. The paper concludes that coordinated operation can contribute to improve the exploitation of energy resources in the prosumer microgrid, reducing the amount of energy interchanged with the distribution grid by approximately 13%, and, at the same time, avoiding increasing the battery cycling and consequent degradation.

The power generation from renewable power sources is variable in nature, and may contain unacceptable fluctuations, which can be alleviated by using energy storage systems. However, the cost of batteries and their limited lifetime are serious disadvantages. To solve these problems, an improvement consisting in the collaborative association of batteries and supercapacitors has been studied. Nevertheless, these studies don’t address in detail the case of residential and large-scale photovoltaic systems. In this paper, a selected combined topology and a new control scheme are proposed to control the power sharing between batteries and supercapacitors. Also, a method for sizing the energy storage system together with the hybrid distribution based on the photovoltaic power curves is introduced. This innovative contribution not only reduces the stress levels on the battery, and hence increases its life span, but also provides constant power injection to the grid during a defined time interval. The proposed scheme is validated through detailed simulation and experimental tests.

This paper presents a new topology for the power injection system that is based on the parallel association of two voltage source inverters. One operates using a quasi-square voltage waveform strategy, and the other operates with a pulsewidth-modulation (PWM)-based strategy. The aims of this topology are to inject the power from the photovoltaic generation system using the quasi-square inverter and to control the current quality using the PWM inverter. The proposal optimizes the system design, permitting the reduction of system losses and an increase of the energy injected into the grid.

A novel multiconverter conditioner topology and its control stage are proposed in this paper. It is formed by an active conditioner in parallel with a hybrid conditioner composed of an active filter in series with one or more passive filters. This topology allows the reduction of the inverter ratings, constituting an effective solution at high-power levels. Collaborative control strategies are developed for the new topology, which share the compensation objectives between the two converters. These control strategies and the tracking techniques are based on estimating the load current, achieving new algorithms with a reduction in the number of meters in the control stage. The conditioner operates properly in three-phase four-wire systems reducing the harmonic distortion and/or imbalance and attaining the unity displacement power factor. Experimental results are included for the testing of the topology and its control.

Microgrids of prosumers are a trendy approach within the smart grid concept, as a way to increase distributed renewable energy penetration within power systems in an efficient and sustainable way. Single prosumer individual management has been previously discussed in literature, usually based on economic profit optimization. In this paper, two novel approaches are proposed: firstly, a different objective function, relative to the mismatch between generated and demanded power, is tested and compared to classical objective function based on energy price, by means of a genetic algorithm method; secondly, this optimization procedure is applied to batteries’ coordinated scheduling of all the prosumers composing a community, instead of single one, which better matches the microgrid concept. These approaches are tested on a microgrid with two household prosumers, in the context of Spanish regulation for self-consumption. Results show noticeably better performance of mismatch objective function and coordinated schedule, in terms of self-consumption and self-sufficiency rates, power and energy interchanges with the main grid, battery degradation and even economic benefits.