Dithering digital ripple correlation control for photovoltaic maximum power point tracking

This work develops and simulates a new maximum power point tracking algorithm for use in switching power converters for photovoltaic applications. Building upon previous work in ripple correlation control (RCC), an average-based RCC approach is introduced which makes use of quasi steady-state converter operation to drive the converter duty ratio to the optimal value. Dithering Digital Ripple Correlation Control (DDRCC) combines the need for high PWM resolution with the need to operate at the panel MPP. Together these two requirements can be used to form a complementary solution in which the technique of PWM dithering for improved average PWM resolution, forms the ripple required for RCC. By sampling data at two selected times during each dithering cycle, the converter is able to converge to the maximum power point of the PV array while avoiding complications previously experienced using the RCC technique at the converter switching frequency.