A 3-D Maximum Power Point Tracking Technique for Energy Harvesting System Based on Hill-Climbing Algorithm

In this paper, a 3-D maximum power point tracking (3-D MPPT) method based on the hill-climbing algorithm for solar energy harvesting system (SEHS) with wide illumination range is proposed. Charge pump conversion ratio, capacitance and working frequency are adaptively adjusted in the proposed 3-D MPPT. By this method, the maximum power point tracking range and precision are greatly improved, which makes the system can be performed in the range of micro light to normal light. An optimized MPPT algorithm is presented to smoothly determine the appropriate 3-D parameters according to the state of solar cells without malfunctions, which can realize internal resistance matching for maximum power extraction from energy source. The system is implemented in a 0.18 mu m BCD process. The verification results show that the proposed solar energy harvesting system with proposed MPPT can achieve maximum power point tracking in different illumination ranges and output a stable 3.3V working voltage with constant turn-on time (COT) mode. The accuracy of the proposed MPPT is up to 99.6%.