The Design Of Household Type Grid PV Inverter Based On K60

In recent years,the intensification of environmental issues and energy crisis has made the countries of the world attach great importance to the field of solar photovoltaic power generation.The Chinese government has also increased its support for distributed photovoltaic power generation.In response to the country's call,distributed generation systems such as rooftop solar photovoltaic power generation have received increasing attention.Its characteristic is that the generated electric energy can be directly allocated to the user's electric load,and the excess or insufficient power can also be adjusted by connecting the electric network.For traditional household PV inverters,there are often some defects.For example,the maximum power point tracking control of solar panels is not good,so that the utilization of solar energy is low;the function is single and can only be run off-grid or Network operation and so on.Therefore,in order to overcome the above defects,this article has improved the household photovoltaic inverter.A household photovoltaic inverter based on K60 control which was designed to enable grid-connected and off-grid operation.Its main work is as followed.Firstly,The main circuit topology,maximum power point tracking,filter parameter design,and control strategy of the household photovoltaic inverter were studied in-depth study.In the topology selection of photovoltaic inverter system,PV inverter topology is divided into two parts:DC/DC and DC/AC.The advantages and disadvantages of various DC/DC circuit structures are compared and analyzed,and the control principle of the DC/AC part is studied.A detailed comparison and analysis of some topologies for household PV inverters was carried out.Finally,a single-phase full-load 1kW inverter topology and its main circuit parameters were determined.It is determined that the pre-stage DC/DC section uses a single inductor Boost transform circuit,and the post-stage DC/AC section uses a two-stage structure of a single-phase bridge inverter circuit structure.Secondly,the output characteristics and circuit model of the photovoltaic cell were studied in depth.According to the research on the output of solar cells,the MPPT(Maximum Power Point Tracking)control principles and methods for solar cells are introduced.The perturbation observation method was selected as the MPPT control method of the system,and the photovoltaic inverter output current was controlled to achieve the maximum power point tracking of the photovoltaic cell.Then,in terms of hardware,the Boost circuit's inductance,supporting capacitance and filter circuit were designed and calculated.The hardware circuit of the K60-based household PV inverteris designed,including embedded microcontroller core board module,power module,IGBT snubber circuit module,frequency and phase detection module,optocoupler isolation circuit module,voltage and current detection module,and auxiliary power module.Altium Designer software is used to draw schematics and PCB diagrams of the circuit board,and then process,weld and debug the designed circuit board.In terms of software and simulation,the control is flexible and simple to use the software phase-locked loop to carry out the same frequency and in-phase control of the system.According to the selected control strategy,the control system was modeled and designed the closed-loop parameters respectively.The software was used to simulate the system and the correctness of the system modeling and design was verified.Finally,combined with laboratory power electronics experimental platform,a family of photovoltaic inverter prototypes based on the embedded single-chip microcomputer K60 was designed,and the off-grid and grid-connected operation of photovoltaic power generation systems was realized as the basic requirements,and the relevant experimental results were given.The results show that the device has high efficiency and can be connected and off-grid.