Converter-less MPPT for rural area applications

A popular method to extract maximum power from a solar PV array is the direct connection of a DC/DC converter to the PV array. It is known as Maximum Power Point Tracking (MPPT) technique. In this approach, the PV array is perturbed at a fractional voltage and few tens of kHz frequency. Drawbacks in this approach of maximum power extraction include oscillations in the DC voltage, reduced conversion efficiency and frequent maintenance of the converters (owing to the frequent failure of electrolytic capacitor), which makes it unsuitable to rural area PV applications. This paper proposes Dynamic PV array (DPVA) approach for extracting maximum power from PV array. In this approach, a switch-network of semiconductor switches or electrical relays is integrated into the PV array to choose a matching-configuration for the load. The absence of high-frequency operation, oscillations in the DC voltage and power processing stages are some inherent advantages of this approach. This paper presents a procedure to design a specific size Dynamic PV array, such that, it produces MPP or close to MPP power at all load conditions. Further, a mathematical relationship between the size of DPVA and the Minimum Output Power (MOP) it can produce is derived. Simulations and a six-module experimental tests are conducted to validate the derived relation.