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RESEARCH PRODUCT

Power dispatching techniques as a finite state machine for a standalone photovoltaic system with a hybrid energy storage

subject

description

Standalone photovoltaic system (SPVS) is usually embedded with an energy storage unit to overcome the intermittency of photovoltaic (PV) generation as well as to address load variations in off-grid operation. In SPVS energy systems, batteries can serve as the long term energy storage and contributing to the large portion of the energy demand but to overcome the load intermittency, it necessitates a fast response energy storage embedded with the battery as a hybrid energy storage (HES) for dynamic loads (e.g., Electric Vehicle loads, emergency power management). In this work, Lead-Acid (LA) battery and supper capacitor (SC) array are used as the HES. HES helps not only in increasing more utilization of PV generated power but also in improving system dynamics and stability for power intensive loads operation. This paper presents innovative power management and control strategies for a HES connected in DC coupled architecture. The presented architecture can also be used for DC micro grids. Power management strategies are developed in a hierarchical architecture as an event driven finite state machine. Primary control is implemented using current mode control and voltage mode control adapted at the bi-directional DC-DC converters and the voltage source inverter connected to the HES, respectively. The performance of the developed power management strategies for the HES is analyzed for typical load dynamics.