Design and implementation of a hybrid maximum power point tracker in solar power system

This paper provides a hybrid maximum power point tracker (MPPT) with both perturbation and observation method and open circuit voltage method in solar power system. The open circuit voltage method is initially used to retrieve the open circuit voltage corresponding to maximum power point. The perturbation and observation method starts up instead while the input voltage of the power converter reaches the calculated maximum voltage. Furthermore, a variable range is defined by the calculated maximum voltages, and the perturbation and observation method is still used for MPPT if the subsequently sensed voltage value falls within this determined range. On the other hand, the open circuit voltage method is reused to function as MPPT again if the sensed voltage value does not fall within the range. That is, the proposed method will omit small power perturbation to decrease the tracking time and oscillation phenomenon at maximum power point caused by conventional perturbation and observation method, and therefore the loss reduction. The duty cycle is set the same as the previous duty cycle while the observed power reaches the predetermined range. HT46F49E MCU is used to implement the proposed MPPT method and a boost converter is utilized to act the power topology. The experiments confirm with the predetermined results.