Research On Optimized Y-source Inverter With The Capability Of Suppressing Effects Of Leakage Inductances

For the purpose of solving the current world energy shortage and alleviating the frequent occurrence of global extreme climate,it is an effective way to accelerate the process of the global energy revolution and achieve the objective of existing energy structure transformation oriented toward low carbon,cleanliness and sustainability with the least delay possible.Among masses of new energy power generation technologies,solar power generation has the advantages of zero carbon emissions and zero marginal cost,and will definitely become the pioneer of this energy revolution in the future,and the main subject of electric energy replacement and clean replacement in the current energy structure transformation.As the core device of entire photovoltaic power generation systems,photovoltaic inverter undertakes the important task of energy conversion that the low voltage direct current produced by photovoltaic array will be converted into alternating current endowed with stable amplitude and frequency.And its performance is related to whether the whole photovoltaic power generation system can meet the basic requirements of safety and quality of electric energy.However,the traditional multistage high-boost micro inverter has some problems such as flimsy short-circuit resistance,high failure probability and waveform distortion.Therefore,this paper proposes an optimized Y-source inverter with the capability of suppressing leakage inductances effects,launches into comprehensive research on topology improvement,working principle analysis and other aspects,whereafter carries out hardware design and prototype construction.The specific contents include the following aspects:Based on the analysis on the essence and defects of traditional Y-source inverter,an optimized Y-source inverter is proposed,which conquers the field of the continuous input current and suppressing the impact of the leakage inductance from the coupled inductor on the inverter performance,and reduce the starting inrush current,the DC link voltage spike and the magnetic core size.Moreover,compared with the traditional Y-source inverter,it applies lower shootthrough duty ratio when considering same voltage gain,which expends the modulation ratio range and improves the quality of the output voltage waveform.Aiming at the dynamic characteristics analysis of optimized Y-source inverter proposed in this paper,a small signal model under LC filtering is established.The influence of circuit parameters such as duty ratio d and modulation ratio M on system stability is analyzed,which provides a certain guiding significance for the selection of components and control variables.To address the problem of voltage spike in DC link of optimized Y-source inverter,the origins are analyzed,and a new Y-source inverter is proposed to suppress voltage spike in DC link.The new topology can completely eliminate voltage spike on DC link and has higher voltage boost capability.In addition,the diode-assisted structure can effectively reduce the device stress and the size of the core of the coupling inductor,which makes up for the volume increase caused by adding more devices to a certain extent.Finally,an experimental hardware platform is designed and built to verify the proposed optimized Y-source inverter with continuous input current and the diode-assisted optimized Ysource inverter without DC link voltage spikes.The superiority of the two new topologies is proved.