Dynamic and compact control of PV standalone system

The escalated use of renewable sources especially Solar PV calls for control methods, the aim being increasing its flexibility toward changing conditions of load and irradiances due to intermittent nature of PV. Thus a standalone PV system is presented suitable 3-phase low voltage applications. The DC-DC converters are connected in forward power stage for boosting PV voltage and as bidirectional interface for battery backup. The system control is such that it avoids battery overcharging or deep discharging by maintaining the battery SOC levels. This is facilitated by the Desired Power Control (DPC) of system algorithm which tracks the PV power according to the load requirements. Major drawback of control of the standalone system is management of excess PV power which is solved by using DPC without the use of dump loads which are difficult to manage. The control of the DC-DC converters is done analytically for accurate tracking the changing references according to the prevailing conditions. The ac voltage regulation of the inverter is enhanced by using the abc-dq transformation and its control is also done analytically. The active power demand is controlled by regulating DC link voltage. The system is simulated in MATLAB/Simulink for all operations and the results are presented along with analysis modelling and control design.