Research On Y-Source Inverter With DC Link Voltage Spike Suppression

In recent years,with the expansion of renewable energy and new power scenarios,the demand for high-boost micro-inverters grow a lot.The conventional high step-up micro-inverter adopts a multi-stage structure including a boost stage and an inverter stage.The inverter stage is very weak in the face of short circuit.So it is necessary to add the dead zone,which causes distortion of its output waveform.In order to solve these of problems,scholars have proposed a new type of topology,namely the coupled-inductor impedance-source inverters.These inverters have the advantages of wide voltage gain range,small distortion,strong anti-interference ability,and single-stage structure.In this paper,the improved Y-source inverter is the research object,and includes the following aspects:Research the reason why the leakage inductance of the coupled inductor leads to the dc-link voltage spike in the improved Y-source inverter.Based on this research,a new topology is proposed to eliminate the DC link voltage spike of the improved Y-source inverter.The voltage stress and the switching loss of the switching transistor will be reduced.A universal voltage spike clamp circuit is proposed for the traditional coupledinductor impedance-source inverter.This clamp circuit which can be applied to all kind of coupled-inductor impedance-source inverters known at present to eliminate their dc-link voltage spikes.At the same time,since the traditional analysis method is very complicated in analyzing such inverters,a new power electronic analysis method is proposed to reduce the calculation amount of the coupled-inductor impedance-source inverters.A simplified model of the impedance network is proposed for the impedance source inverter.Through this model,the switching process of the impedance source inverter can be described and calculated in detail.The model is used to derive the switching loss of the topology studied in this paper,and the simplified model form of other impedance source inverters is comprehensively analyzed.Finally,the Y-source inverter experimental platform is built.The design and selection method of key components are given.The improved Y-source inverter and the topology proposed in this paper is compared in the experimental waveforms and data.The final results prove the correctness of the theoretical derivation and the advantages of the new topology.