An Enhanced Hybrid Grid Connected Photovoltaic System Using Voltage Oriented Controller and Class D Chopper

Abstract

The performance of a shunt interconnection made from a PV system, a three phase grid voltage supply, and a DC shunt motor (DC load) is investigated The PV system participates with maximum powers to the overall interconnection active power flow. It uses a class D chopper circuitry controlled properly by a typical maximum power point tracker (MPPT) controller. The grid has the role of supplying active power in case of any power deficiency needed by the DC motor load. Similarly, it has also the role of absorbing active power in case of any additional power generated by the PV system and not needed by the DC load. This is done by using an AC/DC power electronic converter. The AC/DC power electronic converter operates either under rectifier or inverter modes. The AC/DC power electronic converter is also operated under the next two conditions: 1-the reactive power expected at the grid voltage bus should be nearly null, 2-harmonics currents often encountered in the grid line currents waveforms should be tolerable. The two latter conditions are fulfilled by using the principle of voltage oriented control (VOC) technique. The performance of the investigated interconnection is simulated in Matlab/Simulink platform. Quite satisfactory results are obtained. The satisfaction about the obtained simulation results persists on being able to integrate easily the PV system with the AC grid while extracting maximum power from the PVG and having a unity power factor at the AC grid bus and less encountered harmonics in the ac line currents.