Control Scheme of a Concentration Photovoltaic Plant with a Hybrid Energy Storage System Connected to the Grid

Abstract

Abstract:In the last few decades, renewable energy sources (RESs) have been integrated into the electrical grid in order to curb the deficiency of energy owing to, among other factors, the depletion of fossil fuels and the increasing awareness of climate change. However, the stochastic nature of these sources, along with changes in levels of energy consumption, signifies that attention now needs to be paid for energy storage systems (ESSs). One of the most promising RESs is concentration photovoltaic (CPV) energy, owing to the high efficiency obtained and its sustainability regarding environmental issues. However, as CPV systems work only with direct solar radiation, they require ESSs in order to smooth the variations in the energy generated. This paper deals with the integration into the grid of a CPV plant that employs a hybrid ESS (HESS) based on ultracapacitors and batteries. The HESS allows the complete system to inject a constant active power level into the grid and thus flatten the profile of the energy generated. This goal is achieved by using a power electronic topology based on various DC-DC converters and a DC-AC converter, both of which share the same DC link. The control system is tailored in order to decouple the active-power and the reactive-power injections. Simulation results obtained using PSCAD/EMTDC (Power System Computer Aided Design/Electromagnetic Transient Direct Current) show the resulting performance of a 200 kW CPV plant with a hybrid ESS.

Standalone Photovoltaic Direct Pumping in Urban Water Pressurized Networks with Energy Storage in Tanks or Batteries

“…Researchers have carried out many projects in optimizing the use of PV systems in general (production, storage, scheduling, etc.) [10][11][12][13]. Additionally, their use in irrigation networks has been explored [14][15][16] because of their energy consumption reduction [17,18].…”

Control and Restrictions of a Hybrid Renewable Energy System Connected to the Grid: A Battery and Supercapacitor Storage Case

“…The power balance of the HRES indicates an equilibrium between the produced, stored, consumed and exchanged energy, provided that the voltage of the DC bus is constant. As explained in [15], the power generated from the PV plant, ppv, is equal to: Moreover, inductive filters are used to connect the batteries and the supercapacitors to their respective converters, being L b and R b the inductance and the resistance, respectively, of the connection filter associated to the batteries, and L sc and R sc the inductance and the resistance, respectively, of the connection filter of the supercapacitors.…”

“…The power balance of the HRES indicates an equilibrium between the produced, stored, consumed and exchanged energy, provided that the voltage of the DC bus is constant. As explained in [15], the power generated from the PV plant, p pv , is equal to:…”

“…One of the simplest solution is to calculate the reference of the storage power p st * without taking into account the losses due to the connection filters with a structure based on an open-loop scheme [24,25]. Nevertheless, according to [15], a better possible solution is to use a closed loop scheme for controlling the active power, as shown in Figure 3. The positive sign indicates that the power is injected into the various systems of the HRES, i.e., the storage system, the three-phase section, etc., while a negative sign means that the power is extracted from the system.…”

“…A fully active and semi-active topology for the battery and supercapacitor connections and their control is presented in [11,12], while a hybrid-diode based solution is described in [13]. This work relies on the most common parallel topology of the battery and supercapacitor connection, with a bidirectional DC-DC converter for each energy storage device, since this converter topology offers a better flexibility compared with other configurations and allows a full control action on each converter individually [14,15] with an implementation of a storage system filter in the control system of the ESS.…”