PROJECT TITLE :

A Photovoltaic Generation System Based on Wide Voltage-Gain DC-DC Converter and Differential Power Processors for DC Micro grids - 2017

ABSTRACT:

During this paper, a photovoltaic(PV) generation system primarily based on front-stage differential power processors(DPP) and BACK-stage centralized wide voltage-gain converter is proposed. The resonant switched capacitor(ReSC) converter, that options high power density and high potency, is utilized as the differential power processor and aims at processing the differential power among series-connected PV modules, avoiding the good power loss caused by power mismatch of PV modules. The ReSC converter in PV system can operate in equalization mode or MPPT mode and both modes are researched. The BACK-stage DC-DC converter is implemented as the twin-section-shift controlled full-bridge converter(DPS-FBC). It has high conversion efficiency and wide voltage gain, suitable for PV generation applications. This source control for grid-connected mode and the voltage supply control for islanding mode are developed for DPS-FBC. Thus, for the full system with front and BACK stage converters, the dual-mode management strategy is proposed. When the system is connected to the grid, DPS-FBC operates as the current supply for international MPPT for PV modules while ReSC converters operate in maximum power point tracking(MPPT) mode for native MPPT. When the system operates in an island, DPS-FBC works as the voltage source for constant output voltage management and ReSC converters work in equalization mode. The mode switch is predicated on the voltage of output DC bus. Simulations and experiments verify the feasibility of the proposed PV generation system and the effectiveness of the proposed management algorithm