Solar power controller to drive load at constant power under insufficient solar radiation

In this paper we have proposed, designed, and practically implemented 125V solar power controller (SPC) capable of driving load at constant power under insufficient solar radiation. The SPC consists of two DC-DC converters along with MPPT controllers and a storage battery. One of the DC-DC converters is connected directly to the solar panel and the other is to the storage battery. To extract the maximum possible electric power from the solar panel MPPT controller is used. The converter steps up unregulated solar panel voltage to a regulated 125 V at the load end. The output voltage can be adjusted to any desired level from 20V to 200V DC depending on the application. The proposed controller can provide constant power at 125V and charge the battery when photovoltaic generated power is greater than the load requirements. In contrast, the controller takes additional power from the battery for driving load at constant power with efficiency of about 87% during insufficient solar radiation. The controller can be effectively utilized to drive solar powered loads in real time irrespective of solar radiation.