**Enhanced-Boost Quasi-Z-Source Inverters with Two Switched Impedance Network**

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**Abstract**

In this paper, two topologies are presented for the enhanced-boost quasi-Z-source inverters, namely continuous input current configuration and discontinuous input current configuration of enhanced-boost quasi-Zsource inverters with two switched impedance networks. Similar to enhanced-boost ZSIs, these proposed inverter topologies possess very high boost voltage inversion at low shoot-through duty ratio and high modulation index to provide an improved quality output voltage. Compared to enhanced-boost ZSIs with two switched Z-source impedance networks, these proposed inverter topologies shares common ground with source and bridge inverter, overcomes the starting inrush problem, draws continuous input current and the lower voltage across the capacitors. Moreover, the input ripple current is negligible. This paper presents the operating principles and analysis of continuous input current configuration enhanced-boost quasi-Z-source inverter with two switched impedance networks and compares with ZSI, SL-ZSI, DA/CA-qZSI, and enhanced-boost ZSIs. The theoretical analysis is done and is validated through simulation and experimental results.

**EXISTING SYSTEM: **

In the shoot-through state, the inductors (*L* 1 , *L* 2 ) are charged by the capacitors (*C* 1 , *C* 2 ). In the non shoot-through state, the stored energy in the inductors and input energy is released to the dc-link, which boosts the voltage gain of the inverter in a single-stage, thereby eliminates the dead time and improves the reliability. But, the conventional ZSI suffers from discrete input current, the capacitors has to sustain high voltage, does not share common ground with source and large inrush current during starting condition. The qZSI and improved-ZSI is proposed in 2008 and 2009 respectively, in order to reduce the capacitor voltage stress, to get continuous input current, eliminates inrush current, and shares common ground with the source. But, the boost factors of these topologies is same as that of conventional ZSI as given in (1)

**PROPOSED SYSTEM: **

The boost factor of switched boost inverters is about same as that of conventional ZSIs with less number of passive components. The high-performance qZSI is proposed in [17] has the boost factor similar to ZSI, which reduces the voltage stress across the capacitor and inrush current and shares common ground with the source with the addition of only one extra switch. By replacing one of the SLcell with voltage-lift unit, the topologies provides high boost factor. In order to obtain the high voltage gain, by varying both turns ratio and duty cycle freely, the magnetically coupled inductor/transformer source inverter. The inverters uses more components in the impedance network to get the higher voltage gain, use less components for obtaining the high voltage boost. The main disadvantage of these magnetically-coupled impedance source (MCIS) [19]–[30] networks is that; the coupling must be strong to get low leakage inductance and low spikes in the dc-link voltage. CONCLUSION In this paper, two topologies of enhanced-boost quasi-Zsource inverters with two switched impedance network is proposed, namely continuous input current and discontinuous input current configuration and compares them with conventional ZSI, SL-ZSI, DA/CA-qZSI and enhanced-boost ZSIs. The proposed inverters possesses high boost factor at the low shoot-though duty ratio and high modulation index. The continuous input current configuration of enhanced-boost qZSI is used for theoretical, simulation and experimental analysis. The stress across the capacitors is less so lower rating capacitors can be used, it provides common ground with source and inverter, and overcomes the problem of starting inrush current. Moreover, the input current ripple in the proposed inverters is also zero and it can be negligible.

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