The Optimization Of Photovoltaic Micro Inverter Based On Interleaved Flyback

With the development of photovoltaic industry,distributed photovoltaic system become the future trend.It is noteworthy that AC module photovoltaic system belong ing to distributed system has obvious merits in terms of adaptation to environment,using convenience and security.It neither has the phenomenons of "Partial Shading"and "Potential-Induced Degradation" leading to PV module's degradation,nor has high voltage between its DC bus.Besides,it can be plug and play.The photovoltaic micro inverter is the core part of this system.This research aimed at optimize photovoltaic micro inverter based on interleaved Flyback.It's merits including high efficiency,easy control,concise topology and high reliability.The inverter is optimized from three aspects:power circuit,sampling circuit and controls parameter.For the optimization of power circuit,this research can achieve satisfactory efficiency is expected.Therefore,a power loss analysis on the micro inverter system is maked firstly.And the conclusion that the loss of transformer and the MOS need to be optimized is achieved.Then,according to the result of loss analysis transformer and active clamp circuit are optimized.Finally,put forward the optimization method of the active clamp circuit and a simulation is done to verify.For the optimization of power circuit,It is expected that this research can obtain accurate and reliable sampling value which meet control requirements.Therefore,the ADC sampling frequency and sampling points are optimized firstly,which can both meet the accuracy and the requirements of control.Then the sampling circuit noise is calculated.For the optimization of closed-loop control parameter,the expectation of this research is the current's quality micro inverter output can achieve the requirement of grid-connected.This research respectively optimizes the control parameters of system's outer loop,intermediate grid current loop and the inner share current loop.Outer loop ensure the reference provided to grid current loop do not have harmonic.Inner share current loop ensure Two Flyback current are consistent.Grid current loop ensure the output meet expectations.According to the optimized method this study design a prototype for validation finally.