Design And Development On A Nonisolated Single-phase Photovoltaic Inverter

Solar energy,as a renewable,pollution-free,abundant reserves new energy was widely accepted at present,its research has made great breakthroughs and its development capacity has been great improved in the past half century.Therefore,the development of the core equipment of solar power generation system has also been a research hotspot in the industry.As the last stage and the only stage energy conversion device in solar power generation system,this thesis tade the inverter as the research object and analyzed several key problems.The main work of this thesis includes:Firstly,we had completed the hardware design of inverter,and given the overall scheme which was including the boost circuit,the full bridge circuit and the sampling circuit.In this chapter,the method of synchronous development of circuit design and simulation is proposed,especially for boost circuit and full bridge inverter circuit.After completing the principle design,the corresponding operation simulation is carried out by using MATLAB,in order to get a better performance scheme in the principle design stage.Through the above methods,we successfully solve the problem that the verification cycle of the circuit design was long.Secondly,we had completed the overall scheme of software desig,and analyzed the key modules such as PWM module,MPPT module and AD sampling module.In this chapter,the control system has two functions that the first one was controlled the hardware circuit,and the second one was completed the communication with the host computer or cloud platform.those were the cause of insufficient system resources.Based on the above problems,this thesis proposed a technical scheme of Dual DSP.The master DSP was responsible for controlling the hardware circuit and the slave DSP was responsible for external communication,and SPI communicationwas used between the two DSPs.So the above problems has been solved.Thirdly,we had completed the overall scheme of the structure design,and the detailed design of structure and thermal was completed.In this chapter,because of the problems that the traditional physical prototype has long development cycle and high design cost,so we had proposed a new design scheme called the digital prototype design method which including the structural design,assembly analysis,interference analysis,thermal design in the principle design stage.Finally,we had completed the preliminary performance test of the inverter prototype by using the laboratory test equipment.The test results showed that the design of inverter was accord with the design requirement;The main work of this thesis was complete the design of the 3KW non-isolated inverter.Inverter was the core device in photovoltaic power generation system.It had great value for the expansion of the company in the field of new energy and the development of business lines with core technology when we had competed the micro inverters with high reliability,high efficiency,low power consumption and low cost.