Grid Synchronized Solar Micro-Inverter

Abstract

Normal solar power inverter uses a series parallel combination of solar PV modules to boost the power level at the DC side. A single inverter is used to generate AC power. This type of configuration suffers from partial shading of PV modules that reduces the output generation level. Secondly, during maintenance or breakdown period, total power generation stops. In the proposed system a small inverter is connected with each PV module. The generated AC power from the modules is added at the AC side to boost the power level. Partial shading or breakdown of one or two inverters will not hamper the main production of power. Secondly, replacement of a micro inverter is very easy. Boosting of power needs only adding micro-inverter whereas single inverter based system needs to replace the inverter itself which is very costly. Since the cost of a micro-inverter is very less, one can keep extra standby unit for replacement. Though the initial investment of a micro-inverter based power system will be higher but it can be shown that it is cost effective if we think of more than 2–3 years of use. Each unit continuously senses the voltage, frequency and phase of the grid supply and tracks the generated output voltage accordingly. Three phase configuration also can be achieved by grouping the inverters and connecting those to three phase lines separately. The inverters cover IP 65 specifications thus placing these on rooftop is not a problem. Convention inverter uses high voltage DC at the inverter. Bringing high voltage DC to domestic areas is also a risky affair. The micro-inverter eliminates the problem as it handles low DC voltage at its input. PLCC based communication will be used to monitor the condition of power generation from each inverter from a remote place.