Unsymmetrical, interdigital vibration energy harvester: Bandwidth adjustment based on mode separation technique

Vibration-based piezoelectric energy harvesting technique is a promising way for power supply of smart and mobile wireless sensor networks. The novel structures of harvester with low frequency, wide bandwidth and large output power have drawn great attention. In this paper, vibration energy harvester with unsymmetrical, interdigital pick-up structure and voltage synchronous management circuit have been designed, fabricated, and characterized. The working bandwidths of 11.2 Hz at simulation and 12.3 Hz at experiment have been gained for the designed structure based on mode separation technique in a low vibrational frequency range (below 25 Hz) with the acceleration of 1g. Experimental results show that the proposed harvester can generate the output power of about 151.3 μW (5.91 times of our previous work), which can maintain the normal work of given electronic devices (containing 18 light emitting diodes) by using a matched voltage synchronous management circuit. These results make it a promising candidate for power supply of low power micro electron devices in some special low frequency vibration environment, such as large engineering, bridge monitoring, wildlife monitoring, etc.