1 Introduction

The output characteristics of solar Photovoltaics (PV) cells reveals that the energy harvest can vary greatly depending on the light radiation intensity and ambient temperature. One basic requirement of PV system is always making each PV panel in the system to output the maximum power available. Hence, Maximum Power Point Tracking (MPPT) techniques are widely used to enhance the energy harvest to the maximum, hence getting the best return of the investment.

The conventional MPPT operation, which are widely used nowadays, is carried out at the PV string level, as shown in Figure 1-1. Since each PV string usually consists of multiple PV panels and each PV module consist of multiple PV cells, which are usually connected in series, it only achieves global string MPPT but not module level MPPT. Therefore, each PV module may not work at its own maximum power point, preventing the ultimate maximum energy harvest. To solve this issue, micro inverters are deployed beneath each PV panel, as shown in Figure 1-2, to achieve per-panel level MPPT thus improving the overall power yield performance. In such a configuration, the micro inverter converts each PV panel’s DC power output to grid ac power rails.

Figure 1-1 PV System Deployment with String Inverter

Figure 1-2 PV System Deployment with Micro Inverter