Photovoltaic Grid-connected System Of Energy Storage Inverter Hardware Circuit Design And Development

In order to resolve and handle the limitation problem for photovoltaic on-grid system in Europe countries and Australia,the subsidy for electricity purchase becomes lower while the electricity price gets higher,and installation of new energy power generation devices become more and more,like wind power generation.This leads to an increase in the demanding for the energy storage system;Chinese photovoltaic industry variation trend can be predicted that once the installation of photovoltaic grid connected system reaches a certain quantity,the selling power subsidy will become lower and lower,and finally limit the photovoltaic power sending to grid in the future and truly realize the user self-generation and self-using on clean energy.This thesis researches and designs an energy storage inverter which can be compatible with existing power generation system to realize the photovoltaic on-grid system converting to energy storage system.First of all,according to the properties of the existing power generation system,we determined the working mode of the energy storage inverter.The working mode can be classified into four types:(1)In the day time,the on-grid inverter works normally and the battery is not fully charged;(2)In the day time,the on-grid inverter works normally and the battery is fully charged;(3)During the night,the on-grid inverter does not work and the battery power is plenty;(4)During the night,the on-grid inverter does not work and the battery power cannot fully support the load.According to the energy storage inverter's input and output requirements under different working modes,we can determine the energy storage inverter structure.It should contain microcontroller circuit,sampling circuit,DC/AC converting circuit,AC/DC converting circuit,driving circuit,battery charge and discharge circuit,protection circuit and filter circuit and so on.Then,we investigated and designed the co-work algorithm for all function module circuits to satisfy the energy storage inverter output requirement and battery charge and discharge requirement under different working modes.We decided to choose full-bridge rectifier after studying AC/DC converting principle and method;We decided to use full-control and full-bridge inverter after studying DC/AC converting principle and method;According to different working modes logic,we made selection of microcontroller type and control circuits;we designed different kinds of filter circuits to satisfy main functional modules output requirements.Finally,we tested the complete energy storage inverter to check if all of the testing data meet the requirement and if all of the protection function work normally when it is necessary.