A low cost stand alone photovoltaic scheme for motorized hybrid loads

Abstract

This paper presents a novel error driven online search and tracking controller for maximum PV-solar energy utilization for a low cost cottage electric energy scheme. It proposes a maximum photovoltaic solar energy tracking and efficient energy/power utilization control scheme to cope with changing resistive loads and motor torque variations. The proposed controller requires only the online value of the PV array output voltage and current that can be easily measured with voltage and current transducer. Satisfactory results are obtained with the proposed dynamic tracking controller for resistive load as well as for a permanent magnet DC motor. In this paper the novel dynamic search controller was developed by the first author and is based on dynamic voltage or current error-signals activating a proportional plus integral (PI) controller. For resistive type load the tri loop based PV power, voltage and current tracking controller. This is adequate in ensuring maximum power tracking but for a motorized load driving a blower/fan/pump type mechanical load, the speed dynamic error is also used as input instead of the photovoltaic voltage dynamic error. The proposed stand-alone scheme is a suitable for low cost cottage electricity renewable energy scheme and can be implemented by a low cost PIC 16 micro controller for economic sizes (150 watts-1500 watts).