Topological Study Of High Boost Ratio Y-source Inverter With Low Dc Link Voltage Spike

Under the dual carbon background,the development of renewable energy in China and the world has seen a significant growth,especially the rapid growth of solar installations and power generation.For photovoltaic power generation system,high efficiency inverter is needed to transform the low voltage DC with considerable fluctuation output of photovoltaic array into AC which meets the requirements of grid-connection.However,the traditional voltage source inverter limits its application scope due to its step-down characteristics.Therefore,photovoltaic power generation system urgently needs the inverter with high voltage boost function.Therefore,this paper carries out a detailed study on the coupled-inductor impedance-source inverter which has a wide development prospect.The specific research content mainly includes the following aspects:The principle of extended quasi-Y-source inverter is analysed.In order to address the problem of DC-link voltage spike caused by leakage inductance of coupled inductor,an optimized Y-source inverter topology with low DC-link voltage spike was constructed by introducing a passive absorption circuit.The absorption circuit absorbs the leakage inductance energy,which can effectively restrain the voltage spike of the DC-link,and the topology structure gets the advantages of high voltage boost gain and low voltage stress of the capacitor.A new passive device elimination method is proposed to solve the problem that the analysis process of coupled inductive impedance source inverter is complicated and difficult to be solved by traditional analytical method.The circuit of impedance source inverter is simplified by means of capacitor disconnection and inductor short circuit.Without affecting the calculation results,there is no need to solve the complex integral expressions of capacitance current and inductance voltage,which greatly reduces the calculation amount of voltage stress and current stress process of the paired inductance impedance source inverter.In order to decrease passive devices,a universal active absorption circuit is proposed.By adjusting the position of active absorption loop and Y source impedance network,a family of active absorption loop-Y-source inverter topology is constructed.The topology absorbs peak energy for controlling additional switching on and off,effectively eliminating the DC-link voltage spike.Meanwhile,it also has the advantages of continuous input current,higher voltage boost gain,lower device voltage stress and other advantages that other coupled inductive impedance source inverters do not possess.Finally,an experimental prototype is built and verified experimentally.The experimental results prove the correctness of the theoretical analysis and the superiority and effectiveness of the topological structure.