Vibration energy harvesters for wireless sensor networks for aircraft health monitoring

This paper reports a self-powered WSN system based on piezoelectric energy harvesting and used for aircraft health monitoring. The system consists of three main subsystems, energy harvesting unit, MCU & wireless transceiver unit, and sensors unit. The prototype has dimension of 138 mm (L) × 41 mm (W) × 23 mm (H) with a weight of only 40 grams, making it easily integrated and implemented in an aircraft environment. Simulation results showed that with an excitation of 40 Hz frequency and 0.5 g acceleration on the harvester, the system takes about 3.4 secs to power the system with a selected voltage and another 23 secs to perform the initialization operations of the system. After the initialization, data are measured and transmitted wirelessly with a total energy consumption of 0.65 mJ in one cycle every one second. In addition, a new power management strategy for the applications using capacitors to store harvested energy was proposed. The mechanism relies on the analysis of how much energy has been stored on capacitor to determine the executions of the operations in the system. A novel energy saving interface (ESI) is designed to minimize the power consumption during the voltage measurement and an intelligent algorithm was developed to implement the strategy. Initial experiments show that the adapted Z-Stack and the proposed algorithm can be implemented on the system designed in this paper.