Single Stage Dual Boost Inverter with Half Cycle Modulation Scheme for PV System Applications

Abstract

The objective of this paper is to develop a new voltage source inverter (VSI) that acts as a boost inverter. The proposed inverter topology will acts as inverter and also boosts the output voltage with respect to the applied input. In general, the output voltage (AC) of a conventional full-bridge inverter is lower than the input DC voltage. Boost inverters are used in systems, where the output AC voltage is required to be larger than the input DC voltage. In order to obtain output AC voltage higher than the input DC voltage, an additional step up chopper is usually required at the front end, bestowing a two-stage power conversion which yields increased circuit complexity. Hence, in this paper a Dual boost inverter (DBI) has been developed, as a single-stage converter with advantages of a small structure, reduced power devices, and good buck-boost ability. The conventional modulation strategy (full cycle modulation) of the proposed circuit makes all the switches to operate in high frequency and leads to high voltage/current stress, which in turn results in heavy conduction losses and switching losses. The proposed system uses Half Cycle modulation scheme which use the power switches in half cycle, and can greatly reduce the conduction and switching losses of the power devices. In addition, an improved DBI with two clamping switches is also proposed in this paper, to reduce the current circulation losses in DBI with low switching stress. Thus our proposed topology will achieve higher efficiency with reduced losses and switching stress. The simulation results are presented for DBI model and improved DBI model. An experimental prototype is also developed to realize the Dual boost inverter output (without clamping switches) to validate the simulation results.