The Following two Articles will be helpful. The First one may clear your Doubts.

      1. INTERNATIONAL JOURNAL of RENEWABLE ENERGY RESEARCH

           Kiron Das et al., Vol.3, No.2, 2013

          Grid Connected Micro Inverter System Using Half Bridge Converter

           Kiron Das, Mirza Golam Rabbani

Abstract

This Article focuses a micro -inverter system connected to a grid. Past and present conditions of inverters are also focused. In this topology a dc -dc boost half bridge converter is connected to a low voltage PV side. A Pulse width modulated inverter is also integrate with this converter to supply synchronized current to the grid. An adopted Maximum power point tracking (MPPT) system is used to get maximum output.

A highly nonlinear radiation and temperature dependent I-Vand P -V characteristic curve is shown in below

The boost – half - Bridge converter is controlled by S1 and S2 with complementary duty cycle. Neglect all switching dead bands for simplifications.

The idealized transformer operating waveforms are illustrated. When S1 is ON

and S2 is OFF, vr1 equals to vc1 when S1 is OFF and S2 is ON, the voltage levels are unequal and opposite. At the steady state, the transformer volt -scond is always automatically balanced. In other words, the primary volt -second A1(positive Section) and A2 (negative section) are equal, so are the secondary volt -sec A3 (positive section) andA4 (negative section) are equal.

The inverter output current iinv is pre filtered by a first - order low -pass filter on

the sensing circuitry to eliminate the HF noises………..

A boost half - bridge micro - inverter is presented in this paper. The operation principle is analyzed. Simulation result is shown to verify the circuit. The customized MPPT method is ensured that reliable operation of PV micro - inverter system. So it could be the model of the Distributed Generation system

Link: http://www.ijrer.org/index.php/ijrer/article/viewFile/660/pdf

2.  Grid-Connected Boost-Half-Bridge Photovoltaic Micro inverter System Using        

      Repetitive Current Control and Maximum Power Point Tracking  

      G.Krithiga#1 J.Sanjeevikumar#2 P.Senthilkumar#3 G.Manivannan#4

novel boost-half-bridge micro inverter for grid-connected PV systems has been presented in this paper. Here plug in repetitive current controller was proposed. The boost half bridge dc-dc converter operation, principles and dynamics were analyzed.MPPT control method was developed. A 210W prototype model was developed and its simulation and experimental results were shown to verify the various principles.

This circuit offers minimal use of semiconductor devices, simple circuit, easy to control and operate and also possess low cost and high reliability. The experimental results show high efficiency. The current which is injected to the grid is regulated. Under both heavy load and light load condition, it show low THD and high power factor.

Finally, the customized MPPT method that generates a ramp-changed reference for the PV voltage

regulation guarantees a correct and reliable operation of the PV microinverter system. By using variable

step size, fast MPPT speed and a high MPPT efficiency can be obtained. As a result, the proposed

boost-half-bridge PV microinverter system with its advanced control implementations will be a competitive candidate for grid-connected PV applications.

Ink www.ijrcct.org/index.php/ojs/article/view/741/pdf

P.S.

Thx guy.