scholarly journals Comparative Study of Ramp-Rate Control Algorithms for PV with Energy Storage Systems

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1342 ◽  
Author(s):  
João Martins ◽  
Sergiu Spataru ◽  
Dezso Sera ◽  
Daniel-Ioan Stroe ◽  
Abderezak Lashab
Keyword(s):  
Energy Storage ◽  
Storage Systems ◽  
Control Algorithms ◽  
Energy Storage Systems ◽  
Ramp Rate ◽  
Battery Lifetime ◽  
Smoothing Methods ◽  
Battery State Of Charge ◽  
Rainflow Cycle Counting ◽  
Number Of Cycles

The high variability of solar irradiance, originated by moving clouds, causes fluctuations in Photovoltaic (PV) power generation, and can negatively impact the grid stability. For this reason, grid codes have incorporated ramp-rate limitations for the injected PV power. Energy Storage Systems (ESS) coordinated by ramp-rate (RR) control algorithms are often applied for mitigating these power fluctuations to the grid. These algorithms generate a power reference to the ESS that opposes the PV fluctuations, reducing them to an acceptable value. Despite their common use, few performance comparisons between the different methods have been presented, especially from a battery status perspective. This is highly important, as different smoothing methods may require the battery to operate at different regimes (i.e., number of cycles and cycles deepness), which directly relates to the battery lifetime performance. This paper intends to fill this gap by analyzing the different methods under the same irradiance profile, and evaluating their capability to limit the RR and maintain the battery State of Charge (SOC) at the end of the day. Moreover, an analysis into the ESS capacity requirements for each of the methods is quantified. Finally, an analysis of the battery cycles and its deepness is performed based on the well-established rainflow cycle counting method.

scholarly journals Energy Storage Requirements for PV Power Ramp Rate Control in Northern Europe

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Julius Schnabel ◽  
Seppo Valkealahti
Keyword(s):  
Energy Storage ◽  
Control Strategy ◽  
Storage Systems ◽  
Primary Energy ◽  
Climatic Conditions ◽  
Solar Pv ◽  
Energy Storage Systems ◽  
Ramp Rate ◽  
Performance Requirements ◽  
University Of Technology

Photovoltaic (PV) generators suffer from fluctuating output power due to the highly fluctuating primary energy source. With significant PV penetration, these fluctuations can lead to power system instability and power quality problems. The use of energy storage systems as fluctuation compensators has been proposed as means to mitigate these problems. In this paper, the behavior of PV power fluctuations in Northern European climatic conditions and requirements for sizing the energy storage systems to compensate them have been investigated and compared to similar studies done in Southern European climate. These investigations have been performed through simulations that utilize measurements from the Tampere University of Technology solar PV power station research plant in Finland. An enhanced energy storage charging control strategy has been developed and tested. Energy storage capacity, power, and cycling requirements have been derived for different PV generator sizes and power ramp rate requirements. The developed control strategy leads to lesser performance requirements for the energy storage systems compared to the methods presented earlier. Further, some differences on the operation of PV generators in Northern and Southern European climates have been detected.

scholarly journals An Effective Control for Lead-Acid Performance Enhancement in a Hybrid Battery-Supercapacitor System Used in Transport Vehicles

2021 ◽  
Vol 13 (24) ◽  
pp. 13971
Author(s):  
Mpho J. Lencwe ◽  
S. P. Daniel Chowdhury ◽  
Thomas O. Olwal
Keyword(s):  
Energy Storage ◽  
Performance Enhancement ◽  
Storage Systems ◽  
Lithium Ion ◽  
Simulation Software ◽  
Effective Control ◽  
Energy Storage Systems ◽  
Battery Lifetime ◽  
Dc Bus ◽  
Lead Acid

Modern vehicles have increased functioning necessities, including more energy/power, storage for recovering decelerating energy, start/stop criteria, etc. However, lead-acid batteries (LABs) possess a shorter lifetime than lithium-ion and supercapacitors energy storage systems. The use of LABs harms the operation of transport vehicles. Therefore, this research paper pursues to improve the operating performance of LABs in association with their lifetime. Integrated LAB and supercapacitor improve the battery lifetime and efficiently provide for transport vehicles’ operational requirements and implementation. The study adopts an active-parallel topology approach to hybridise LAB and supercapacitor. A fully active-parallel topology structure comprises two DC-to-DC conversion systems. LAB and supercapacitor are connected as inputs to these converters to allow effective and easy control of energy and power. A cascaded proportional integrate-derivative (PID) controller regulates the DC-to-DC converters to manage the charge/release of combined energy storage systems. The PID controls energy share between energy storage systems, hence assisting in enhancing LAB lifetime. The study presents two case studies, including the sole battery application using different capacities, and the second, by combining a battery with a supercapacitor of varying capacity sizes. A simulation software tool, Matlab/Simulink, is used to develop the model and validate the results of the system. The simulation outcomes show that the battery alone cannot serve the typical transport vehicle (TV) requirements. The battery and output voltage of the DC-to-DC conversion systems stabilises at 12 V, which ensures consistent DC bus link voltage. The energy storage (battery) state-of-charge (SoC) is reserved in the range of 90% to 96%, thus increasing its lifespan by 8200 cycles. The battery is kept at the desired voltage to supply all connected loads on the DC bus at rated device voltage. The fully active topology model for hybrid LAB and supercapacitor provides a complete degree of control for individual energy sources, thus allowing the energy storage systems to operate as they prefer.

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