Modeling and Design of an Efficient Magnetostrictive Energy Harvesting System With Low Voltage and Low Power

Based on the established equivalent circuit model of a magnetostrictive vibration generator, the low ac voltage and low power produced by the generator under low acceleration are calculated. Comparisons between the calculated and measured results show that the model can provide reasonable data trends of the generator under different loads. To boost the low ac voltage to a high dc voltage required by electronic devices in low power consumption, two energy extraction circuits (EECs) (i.e., a proportion integration-based EEC and an improved EEC) are studied. The corresponding two harvesting systems, which include the generator and the proposed EECs, are designed and simulated in LTspice for system-level evaluation. It is found that the two harvesting systems can effectively boost a few hundred millivolts of ac voltage to the steady dc voltage under low acceleration and varying load conditions. Moreover, the system with the improved EEC can be powered by the harvested energy to maintain self-sustaining operation, and the batteries in the system can be charged for future start-up operations; thus, the system has strong practicability in the dc supply for the electronic devices.