Periodic Reporting for period 1 - IMPRESS (Integrated Modular Power Conversion for Renewable Energy Systems with Storage)
Berichtszeitraum: 2019-10-01 bis 2021-09-30
The action investigates existing preeminent topologies for Distributed Renewable Energy Source with Storage (DRESS) and proposes a novel optimized arrangement for such integrated energy systems. An optimized control algorithm for the effective operation of the sources, PV and battery, within the modules integrated into the ac grid will be studied. Energy-efficient algorithms for the optimized operation of DRESS will be proposed considering various modes of operation. The existing performance monitoring and diagnostic methods in the modular inverters will be studied and a robust diagnostic method for integrated battery and PV unit will be developed to increase the availability of DRESS. The final application of this action will be to produce applicable robust distributed local energy systems using PV and storage to maximize energy generation and increase availability.
In work package 2, the action has investigated innovative ways of integrating PV panel and battery pack such that the need for the additional dc-dc converter is eliminated. Such a solution not only results in high efficiency in the range of 99-99.6% but the reduced cost due to the elimination of dc-dc converters leads to a reduction in LCOE. The aim of doing so is to achieve a scalable, high-efficiency integrated PV-battery solution with decreased LCOE compared to traditional solutions in the market despite higher CAPEX. At the same time, it is observed that the performance of the battery is also enhanced due to the inherent pulsation current through the battery cells.
In work package 3, the action has studied the close interaction between the pulsating current through the battery due to the new configuration. It was initially thought that the pulsed current produced by the proposed solution would improve the battery charging performance. However, this was not found to be true. Through experiment, it was observed that the degradation of the lithium-ion battery in case of pulsed current charging was lower when compared to the traditional charging method (constant current - constant voltage. The proposed solution inherently generated pulsed current. The improvement in the lifetime of the battery was higher than 20% and for the specific case, a 50% higher cycle life was observed for NMC batteries. Such an extension in the lifetime of the battery will prove to benefit applications such as photovoltaic systems in bringing the LCOE lower than the current state-of-the-art systems with Lithium-ion battery storage.