The Design And Implementation Of 8kW Teaching System About Grid-Connected Photovoltaic Power Generation System

With the rapid development of the global economy and the rapid development of human society and population,the society is facing with the serious problem of environmental pollution and energy shortage.Countries around the world have also reached a consensus on the relevant parties which is to increase the adjustment of energy structure and vigorously develop new energy sources,making the situation of environmental pollution have been eased.Among them,the solar photovoltaic power generation system is a high reliability,high cleanliness characteristics.with its endless inexhaustible advantages solar photovoltaic power generation system becomes the object of study.With the rapid development of solar photovoltaic power generation system,people consider the photovoltaic power generation system into the grid in order to facilitate the use of electricity at the same time to alleviate the load pressure of the city network and provide related ancillary services.This paper mainly designs a teaching system about grid-connected photovoltaic power generation system which aims to provide students with teaching experimental platform,so as to understand the solar energy as a new energy to provide energy and master the working principle of solar photovoltaic power generation system.Through the learning of the platform,master the design method of photovoltaic power generation system and installation considerations.The system ensures the reliability and security,while enhancing the experimental display,facilitating students to learn and practice.The main contents of this paper are as follows:(1)On the basis of the introduction and analysis of the working principle of solar cells,the specification and quantity of solar panels and the corresponding series-parallel distribution are determined according to the demand of grid-connected photovoltaic power generation.Analyze the technical specifications of the grid-connected inverter and determine the relevant technical requirements for the grid-connected inverter.And the overall design scheme of 8kW PV grid-connected power generation system for teaching has been determined.(2)On the basis of analyzing and studying the working principle and mathematical modeling of DC/DC step-up converter circuit and three-phase inverter circuit,according to the conventional requirements of PV grid-connected system,the hardware design and component selection of the total circuit of the system are determined.type.The selection of hardware circuit and device is given,which provides hardware support for the design and implementation of control strategy.(3)Based on the requirement of PV array high efficiency operation and grid-connected inverter high power factor and DC bus voltage stability,the maximum power point tracking control strategy based on DC/DC step-up circuit and inverter Double Closed-Loop Control Strategy of DC Bus Voltage.The maximum power point tracking control strategy can control the operating point and output power of the PV array through the DC/DC step-up circuit to make it run at the maximum power output state and improve the efficiency of photovoltaic power generation.The double closed-loop control strategy can make the inverter DC bus voltage stability,to provide a good working environment for the DC/DC step-up front-end;dual closed-loop control strategy can also ensure low AC reactive power component,to improve the power of the grid Factor.(4)The simulation experiment platform of PV grid-connected teaching experiment system is built up by Matlab/Simulink platform,which verifies the correctness and feasibility of the proposed scheme.The physical platform is built in the laboratory,and the experiment is carried out.The effectiveness of the program and maneuverability.