| Energy demand worldwide is increasing rapidly, mainly due to the world population increase and secondly due to the rapid industry advances of recent years .Thus ,with this mind ,the present rate of fossil fuel consumption will lead to an insufficient energy needed to satisfy world demand in the future .Therefore , renewable energy sources are the solution to the world's energy demanded especially to our country of large populations .There is plenty of solar energy resource in our county .PV powered pumps are important to the people in the west of the country ,where electric power is not available . With the decrease in PV cost, PV systems are growing in size. Solar energy is more widely used . There have been major improvements in the cost, efficiency and reliability of PV systems over the last two decades .Moreover there have been major improvements in the cost, efficiency and reliability of PV systems over the last two decades .Therefore it is necessary to improve efficiency of the device. Proper system design and good matching between the different components of a photovoltaic system, should be capable of improvingoverall system efficiency.In this paper, PV powered pump is designed trying to be met with the PV .It is devised to trace the maximum PV powered points .The main contents are listed as follow:1. Introducing the actuality and foreground of PV sources abroad or our country. The basic structure and types of the PV source also are presented. Holding apprehend in the mass to the system.2. this paper has studied on the basic principle and output characters of PV cell. The emphasis is on the output characters and its effect factor. Drawing a conclusion at last.3. The output of PV is non-linear, which has MPPT problem. This paper has studied MPPT method, and proposed improved measures .Especially, PV powered pumps has its own character. Its method of tracing the maximum PVpowered points is realized in this design.4. utilization of stand-alone photovoltaic (PV) array feeding brushless DC motor is controlled by three phase inverter, and use pulse-width modulated (PWM) so that the maximum available solar power of the PV array is always tracked for all varying ambient temperature and solar irradiation levels, as well as for any small variations of the electrical load.5. 8 bit microprocessor of P89LPC932 is used to constitute digital control system of PV powered pump .The control system is designed using ProtelDXP.6. using the integrated chips of ML4425 realized the drive circuit of BLDC. The ML4425 PWM motor controller provides all of the functions necessary for starting and controlling the speed of Brushless DC (BLDC) motors without Hall Effect sensors. Back EMF voltage is sensed from the motor windings to determine the proper commutation phase sequence using a PLL. This patented sensing technique will commutate a wide range of 3-Phase BLDC motors and is insensitive to PWM noise and motor snubbing circuitry ?... |
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