ABSTRACT: This paper proposes a single-phase two stage inverter for grid-connected photovoltaic systems for residential applications. This system consists of a switch mode DC-DC boost converter and a H-bridge inverter. The switching strategy of proposed inverter consists with a combination of sinusoidal pulse width modulation (SPWM) and square wave along with grid synchronization condition. The performance of the proposed inverter is simulated under grid-connected scenario using MATLAB. Furthermore, the intelligent PV module system is implemented using  a simple maximum power point tracking (MPPT) method utilizing power balance is also employed in order to increase the systems efficiency.

KEYWORDS: Photovoltaic; DC-DC Boost Converter; MPPT;SPWM; Square Wave; Power Electronics; Grid Tie Inverter(GTI)

I.INTRODUCTION

In the present scenario of world energy sector renewable sources are growing their importance day by day. This is mainly because of limited resource and bad environmental impacts of the conventional energy. Among the  all renewable energy resources available, solar energy seems to be a major competitor as it is abundant in nature and its conversion to electricity through photovoltaic (PV) process is pollution-free. Increasing interest in PV systems, demands growth in research and development activities in various aspects such as Maximum Power Point Tracking (MPPT), PV arrays, anti-islanding protection, stability and reliability, power quality and power electronic interface. With increase in penetration level of PV systems in the existing power systems, these issues are expected to become more critical in time since they can have remarkable impact on the overall system performance. More efficient and cost-effective PV modules are being developed and manufactured, in response to the concerns raised by the PV system developers, utilities and customers.

Tracking the maximum power point (MPP) of a photovoltaic (PV) array is usually an essential part of a PV system. As such, many MPP tracking (MPPT) methods have been developed and implemented. The overall simplicity and efficiency of PV system depends on the MPPT technique employed. Various alternatives architectures for grid connected PV system configurations are available, such as centralized module, AC module and modular configuration where the last topology perfectly fits with an intelligent PV module concept. The AC module configuration, which is a simplified version of the centralized inverter topology. Here a single string of PV module is connected with an inverter. Each string can be applied with a separate MPPT, as there is no loss attributed to string diodes. In comparison to the centralized inverter the overall efficiency is increased. A common inverter is joined with multiple strings connected to inpidual DC-DC converter. The benefit of this modular configuration over centralized system is that each string can be controlled inpidually and ensure less cabling loss thereby enhancing the overall system efficiency.

Therefore, we proposed a two-stage intelligent PV system, which is similar to modular configuration topology. In an intelligent  PV module instead  of  interconnection  between  modules they are interconnected  with  associated   DCDC 

International Journal of Advanced Research in Electrical,Electronics and Instrumentation Engineering (An ISO 3297: 2007 Certified Organization)

Vol. 4, Issue 2, February 2015 

converter for MPPT tracking which ensures optimal operations of PV module. Various MPPT algorithms exist in different literatures. In this research, we propose perturb and observe (P&O) method to extract  maximum possible power from solar panel. In this article, a two-stage PV system is proposed which consists of a DC-DC boost converter with MPPT, and a DC-AC inverter to convert photovoltaic DC voltage into line 50 Hz AC voltage as shown in Fig. 1.2. In order to minimize the switching losses and to achieve better performance of the inverter, a combination of SPWM and a square wave signal is used for switching the inverter circuit. 太阳能最大功率点追踪和逆变控制英文文献和中文翻译:http://www.youerw.com/fanyi/lunwen_205049.html