Novel Cuk-Buck MPPT Battery Charger for Standalone PV-Inverter Applications

摘要

The theme of this paper is a novel MPPT converter for battery charger. The converter combines both cuk and buck converters topologies to extract maximum power from photovoltaic arrays while supplying a controlled constant current/voltage to the battery simultaneously. The new topology uses two control signals instead of one control signal; one for maximum power point tracking, another for battery charger control providing constant current/voltage to the battery. The Advantage of this converter is to exploit the maximum power of the PV array avoiding battery damage caused by variable MPPT voltage. As a matter of fact, the tracking voltage that tracks the maximum power is variable according to weather irradiation conditions. However, batteries need constant voltage and current for charging to avoid the damage and to extend its lifetime. Therefore, it is reliable to combine the battery charger control and the maximum power exploitation using two control signals simultaneously. The real-time implementation of the cuk-buck converter was carried in TMS320F28335 DSP. A 4kW prototype system was built and four 12V lOOAh batteries were used. The effectiveness of the proposed converter was tested in both simulation and experiment in various operating conditions. The experiment results verified that the PV power obtained of the two control signal converter was exploited better than that of one control signal and that battery's full charging state was reached in a relatively short time.