| In the field of research on solar power generation systems has two major problems,one is how to improve the conversion rate and the utilization rate of solar energy,anther is how to reduce the manufacturing cost of power generation system.Based on Siemens PLC(Programmable Logic Controller)and other automation products,this dissertation designs an independent photovoltaic power generation system with simple structure,low cost and high precision,which can effectively solve the problem that the light sensor is insensitive to the intensity of sunlight,and increase the requirements of "seasonal switching" and "real-time monitoring" in function.It can be used for teaching and civil use,also can effectively solve the resident electricity consumption in remote areas and tourist areas where are not covered by conventional power grid,meanwhile does not cause any environmental pollution.This dissertation focuses on three parts which are light source tracking control,energy storage and inversion,monitoring link.This dissertation adopts the hybrid control mode of "sensor tracking & program tracking",puts forward the use of "multi-mode time-share tracing " design idea.Such as sunny,light sensor can be used to track the sun automatically;If it’s cloudy,solar panels are used to track the sun in time-sharing mode;If the night mode,the solar panel would be laid flat and no longer tracks.In the energy storage and inversion part,the maximum power point is calculated according to MPPT theory,so that the solar panel can output more Power storage energy and supply the batteries steadily,so as to improve the charging efficiency.When inverter works,using pulse width modulation(PWM)output alternating current to the load,also adding the switching power to PLC power supply.Finally,in order to meet the needs of teaching,DC ammeter,DC voltmeter and multifunctional power meter are added in the monitoring link.Load voltage and current data are acquired in real time by MODBUS communication.Human-computer interaction interface is designed by MCGS configuration software which highlights the people-oriented concept and facilitate users to view and use in teaching. |
