A Direct AC–DC and DC–DC Cross-Source Energy Harvesting Circuit with Analog Iterating-Based MPPT Technique with 72.5% Conversion Efficiency and 94.6% Tracking Efficiency
The proposed cross-source energy (CSE) harvesting system accepts universal energy sources, including the ac and dc sources. The buck-boost conversion of CSE automatically converts ac or dc input into dc output without being limited by the type of universal energy source. The CSE technique simultaneously supplies the regulated output for the system loading and the battery charging output. A test chip fabricated in the VIS Bipolar, CMOS, and DMOS (BCD) process can optimally derive harvest energy with 72.5% power efficiency when one solar input source is used. A backup converter is designed to complement the CSE technique to guarantee the regulation of output voltage. The proposed analog iterating-based (AIB) maximum power point tracking (MPPT) technique achieves 94.6% tracking efficiency without complex data calculation and storage, which are better results compared with those of previous research.