Dual-axis Solar Tracking System Based On Ultrasonic Motor

This subject is supported by the national key basic research and development program (973program)(2011CB707602) and the national natural science foundation of China (51175250).Ultrasonic Motors (USM) is a kind of motors with low revolving speed, high torque,especiallypower failure self locking and many other merits. USM is applied to dual-axis Solar tracking systemsin this paper, in order to improve solar battery photoelectric performance, and make it have the higheroptoelectronics convert efficiency. This paper designed a framework of double degree of freedom,which is driven by USM, to make solar battery board can revolve to any direction of sky and achievetracking purpose. A control system is designed based on MSP430MCU, which acquisition signals byphotoresistor light sensor array, to determine the position of the sun and control the USM to drivesolar battery to track the sun. it achieve the purpose of high efficiency energy gathering. Thesystem has a simple structure, energy saving and other advantages.This paper summarized below:1. Introduction of USM development, characteristics and application, and current internationaldevelopments and prospects of solar energy, as well as several common methods and structure theoryof tracking system. With many advantages of USM, we discussed the solar tracking system demandfor motor,Get a conclusion that USM is Suitable for solar tracking system.2. This paper describes the mechanical structure design and characteristics of the solar trackingsystem, including design of worm gear and selection bearing. Then do the dynamics simulation for theentire tracking system by using the ADAMS virtual prototyping software.3. Introduce details of the controller MSP430microcontroller which is used in the solar trackingsystem, and the hardware circuit of the system requirements and designments.4. Introduce software base on the hardware of the above, explain how to achieve the tracking systemprogram on these hardware environment, including: AD acquisition program; tracking controlprogram; key control program; serial communication protocol and so on.And introduce the PCprogram written in this article. PC program is responsible for displaying voltage and current datagraphically which is uploaded and collected by lower computer, in order to compare the promotionof tracking performance.5. We tested the Photoresistor array sensor and level position sensor signal, to reveal thesignal characteristics.The USM drive signals are also measured to verify the drive is working well.Finally, the over all test of the whole system, Panels output voltage and power were compared under fixed state and tracking state, to verify tracking system performance.