Research Of Y Source Inverter Topology And Grid-connected

The inverter occupies an important position in the new energy generation grid-connected system such as solar energy and wind energy.It is the intermediate link between the new energy power generation system and the users and the public power grid.Impedance network inverter represented by Z-source makes up the deficiency of traditional inverter,However,the traditional Z-source inverter has low boost capacity and start-up shock circuit.The improved Z-source increases the voltage gain by increasing the boost unit,which leads to the increase of the volume,cost and power consumption of the inverter.The traditional Y-source inverter using a three-winding coupled inductor,which can significantly improve the boost capacity by changing the winding factor,and reduse the use of components.However,the conventional Y-source has problems such as excessive voltage stress,current interruption,and leakage inductance.Therefore,research on Y-source inverter has theoretical and practical value.The main research contents of this paper include the following aspects:Firstly,the working principle of the traditional Y-source inverter is analyzed,and the problems of excessive capacitance and leakage stress and leakage inductance of the traditional Y-source are described.By changing the coupling inductance connection mode,another Y-source topology is obtained,which has the same performance as the traditional Y-source.In view of the high capacitor pressure,change the cathode connection position of the Y-source inverter capacitor,which can reduce the capacitor voltage stress,and build a simulation model to verify.Secondly,the modulation strategies of several Y-source inverters are analyzed.Among them,the modulation of shoot-through segmented SVPWM not only broadens the range of modulation system and has a small switching tube voltage stress,but also has a small power switch loss,inductance current and capacitor voltage ripple.In the design of impedance network,inductance and capacitance with a small capacity can be selected,which has obvious advantages compared with other modulation strategies.Thirdly,a variety of quasi-Y source inverters are obtained by increasing the inductance and capacitance and changing the coupling inductance connection in the traditional Y-source inverter topology.The quasi-Y source input current is continuous,and can suppress part of the leakage inductance and reduce the peak voltage.Alow-loss absorption loop is proposed based on the quasi-Y source for the voltage spike around the switch due to the leakage inductance of the coupled inductor.The loop can absorb the voltage spike generated by the leakage inductance,reduce the switching loss,and play the role of energy recovery.Set up a simulation model for verification.Finally,the grid-connected modeling analysis is carried out based on one of the quasi-Y source inverters.According to this,the grid-connected current inner loop decoupling control and DC link voltage outer loop control strategy are designed.The system simulation model is built.The simulation results show that The system has good stability and dynamic performance to achieve the expected indicators.Figure [43] table [7] reference [60]...