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 study presents a way of using the photovoltaic power plants for helping the grid to regulate the point of common coupling voltage, not only for injecting active power. This functionality of the photovoltaic resources has become a need as some countries’ standards propose renewable energy to increase the voltage when a sag happens. In addition, this philosophy could also be applied in smart grids where the power must be controlled by the distributed generation. In this study, active power injection is developed by a reference power point tracking and reactive power regulation is carried out by controlling the node voltage, both with dq current control under different power priority possibilities. The generic flow diagram of the control algorithm was implemented on a single‐stage traditional inverter topology. The whole system has been checked with a simulation model, including the control algorithm, in order to tune the controller for obtaining the best performance. Finally, an experimental prototype was implemented for validating the proposed node voltage regulating method.

An autoadjustable synchronous reference frame for extracting the positive-sequence fundamental component of the voltage in the point of common coupling is proposed in this paper. It operates suitably under unbalanced and distorted input voltages, with no steady state error in amplitude, phase and frequency tracking. The dynamic response of the method in case of frequency or amplitude variations is good, achieving the steady state in only two cycles of the fundamental period. The method allows a simple adaptation for being used in single-phase systems too. Simulation and experimental results are presented to test the novel method.

The future of the grid includes distributed generation and smart grid technologies. Demand Side Management (DSM) systems will also be essential to achieve a high level of reliability and robustness in power systems. To do that, expanding the Advanced Metering Infrastructure (AMI) and Energy Management Systems (EMS) are necessary. The trend direction is towards the creation of energy resource hubs, such as the smart community concept. This paper presents a smart multiconverter system for residential/housing sector with a Hybrid Energy Storage System (HESS) consisting of supercapacitor and battery, and with local photovoltaic (PV) energy source integration. The device works as a distributed energy unit located in each house of the community, receiving active power set-points provided by a smart community EMS. This central EMS is responsible for managing the active energy flows between the electricity grid, renewable energy sources, storage equipment and loads existing in the community. The proposed multiconverter is responsible for complying with the reference active power set-points with proper power quality; guaranteeing that the local PV modules operate with a Maximum Power Point Tracking (MPPT) algorithm; and extending the lifetime of the battery thanks to a cooperative operation of the HESS. A simulation model has been developed in order to show the detailed operation of the system. Finally, a prototype of the multiconverter platform has been implemented and some experimental tests have been carried out to validate it.

This study presents a new single‐phase topology for the power injection system of a grid‐connected photovoltaic generation system that is based on the parallel association of two voltage‐source inverters: one is a three‐level inverter with clamping diodes (or neutral point clamped) with a low switching frequency strategy (equal to the grid frequency) and the other is a two‐level inverter which operates with a current hysteresis band strategy and an usual switching frequency (5–20 kHz). The main advantage of the proposed topology is to optimise the system design, allowing high power injection with a significant reduction of system losses (mainly switching losses) and achieving an increase of the energy injected into the grid. The performance of the proposed topology and its control algorithms are tested and validated using a laboratory prototype.

This paper presents a model of two very common inverters, a traditional inverter and neutral point clamped inverter, for calculating the losses in function of the parameters of the inverter datasheet. The model allows simulating the inverter branch under any conditions, not only nominal sinusoidal, and monitoring its losses at the same time, so the most significant parameters could be determined in losses terms. The optimization of the losses in inverters could create an important energy saving since it is present in most of the power applications, mainly renewable energies. Obviously, the model is based on the electrical equations of both semiconductors inverters so the mathematical development is exposed. Finally, the model is validated by solving the equations analytically together with the model simulation under nominal sinusoidal environment. DOI: http://dx.doi.org/10.5755/j01.eee.20.5.7106