Study On A Novel Solar Photovoltaic Control System

As the worldwide energy shortage problem becoming increasing serious, solar as the ideal alternative energy recognized internationally is being used more and more widely. But the general solar system exists the low efficiency of solar light absorption and solar cell power in the same external environment, and the two problems results the waste of the solar resource and the solar power device. So a novel solar photovoltaic power control system was presented in this dissertation, which improved the working efficiency of the solar power system by improving the solar light absorption and the output of the solar cell.From the sun trajectory from the running regulation of the sun to the earth, a tracking method the photoelectric tracking method was proposed in this dissertation according to the varying at all times of incident angle of solar light. The method tracking the sun rays in both pitch-level directions, to keep solar panels perpendicular with the sun rays. It proposed the solar rays absorption of the solar panels. Two three-phase hybrid stepper motors were selected as the implementation components. And according to the problems of the low-frequency oscillation and noise, this article proposed uniform subdivision and constant torque control method, using sine wave subdivision circuit tracking pulse-width modulation to implement the subdivision control of the three-phase hybrid stepper motor. DSP(1) TMS320LF2407A were both used in dual-axis tracking unit and stepper motor control unit, and the system has achieved good control effect.In the solar power system, the output characteristic of solar cells is non-line, and it is easily interrupted by light intensity, environment temperature and load effects. Coming from the basic principles and mathematical models of the maximum power point tracking(MPPT), the article analysis the basic methods to output power of the solar cell. And proposed using the Cuk circuit to control the working voltage point of the solar system, and using the variable step-size admittance increment method started by CVT to implement the maximum power point tracking. Using DSP(2) TMS320LF2407A as the core processor to complete the calculating of MPPT, the system used the PWM wave to control the turning on and turning off of the switch of Cuk circuit, and further controlling the voltage of the main circuit. Simulation results have showed the output power and respond speed and stability of the system have been improved greatly. For example, when solar cells were obscured by clouds and sun light recovered, the process tracked the maximum power point fast, and the solar cells putout by maximum power tracking.