Dual-Input-Single-Output Boost Converter with Inductors Coupling For Dual Electromagnetic Energy Harvesters

Multi-source Electromagnetic energy harvesting is a promising technique for self-powered widely distributed information devices in IoT to improve the output power capability. A dual-input-single-output boost converter is proposed in this paper for dual electromagnetic energy harvesters at different source voltages and internal resistors. To ensure high power delivery, impedance matching is required. The correct duty ratio ranges are investigated for the proposed converter under DCM operation for both branches with same boost inductances. Furthermore, negative coupling between boost inductors will enable current ripple reduction and help for efficiency improvement as well as size reduction. The optimal coupling coefficient for dual electromagnetic energy harvesters at different source voltages and internal resistors is revealed as well as the effective region. The proposed prototype is designed with GaN HEMT power transistors at switching frequency of 250 kHz for input voltages of 5V and 2V, internal resistances of 50ohm and 100ohm, respectively. The optimal coupling coefficient is 0.12 with peak ripple reduction rate of 12.9%. The peak converter efficiency reaches to 94.1% with 1kohm load.