A High-Efficiency and Low-Cost Converter for Photovoltaic Water Pumping System

This project proposes a novel converter for photovoltaic (PV) water pumping or management systems without the use of Chemical storage elements, such as batteries. The converter is designed to drive a three-phase induction motor directly from PV energy. The use of a three-phase induction motor presents a better solution to the commercial dc motor water pumping system. The development is oriented to achieve a more efficient, reliable, maintenance- free, and cheaper solution than the standard ones that use dc motors or low-voltage synchronous motors. The developed system is based on a current-fed multi resonant converter also known as resonant two-inductor boost converter (TIBC) and a full-bridge three-phase voltage source inverter (VSI). The classic topology of the TIBC has features like high voltage gain and low input current ripple. The resulting performance enhancement is demonstrated experimentally. These techniques vary in many aspects as simplicity, convergence speed, digital or analogical implementation, sensors required, cost, range of effectiveness, and in other aspects. This paper is study about high efficiency and low cost of pv water pumping system. To complete our analysis a simple discussion about the cost of the MPPT technique is presented. An adjustable MPPT costs comparison can be carried out by understanding the technique (analogical or digital) accepted in the control device, the number of sensors, and the utilization of an additional power element, considering the other costs (power components, electronic components, boards, etc) equivalent for all the devices. The MPPT execution typology greatly based on the end-users knowledge, accompanied by the analogical circuit, SC, OV, or CV are good alternatives, otherwise accompanied by the digital circuit that demands for the utilization of microcontroller, P & O, IC, and temperature techniques are sufficient easily to implement. Moreover it is important to underline that analogical implementations are generally cheaper than digital (the microcontroller and relative program are expensive). To make all the cost comparable among them, the computation cost comparison is formulated taking into consideration the present distribution of MPPT techniques. The number of sensors needed to execute the MPPT technique also affects the final costs. Most of the time, it is simpler and more reliable to calculate voltage as comparison to that of current and the current sensors are generally more expensive and heavy. The irradiance or temperature sensors are much costly and not common in use. After these considerations, a simplified classification considering the costs of sensors, microcontroller and the additional power components are to be taken.