Design And Verification Of Piezoelectric Energy Harvesting System For Railway Safety Warning

With the development of global economy and the increasing demand for rail trains,the safety warning of train operation and the power supply technology of key equipment become very important problems.Existing train units mainly rely on catenary power supply,while some internal combustion locomotives rely on diesel generators for power generation.However,most common speed trains and freight trains have complex electrical components in the compartment,and some of the cabin power supply is limited or no power supply,so the power supply of safety warning equipment can not be effectively guaranteed.In order to solve the above problems,an energy acquisition method based on the vertical vibration of train mechanical components is proposed in this paper,which realizes the cable-free self-power supply operation of some safety warning devices.Through the research on vibration characteristics of typical mechanical components of railway train,the overall design scheme of piezoelectric energy trap is determined,the double-piezoelectric electromagnetic coupling energy trap mechanism is designed and the electromechanical energy conversion model is established,and the mechanism of mechanical vibration energy collection and energy conversion for train operation is elaborated,which is verified by experiment.Based on the vertical vibration characteristics of mechanical components of railway trains during operation,a bi-piezoelectric electromagnetic coupling energy capture device is studied in this paper.It provides theoretical value and reference significance for the development of new generation of self-powered equipment for trains.Firstly,the vibration characteristics of mechanical components during train operation are studied and important technical indexes of piezoelectric energy trap are determined.It mainly includes in-depth analysis of time-domain and frequency-domain characteristics of vibration characteristics of typical train components,such as body,bogie,wheel pair and Under-Rail support block,and obtaining performance index of working bandwidth of the captured device based on its frequency spectrum characteristics.At the same time,the power consumption requirement of on-board safety warning equipment is analyzed to obtain the power level requirement of captured energy generation.Secondly,a bi-piezoelectric electromagnetic coupling energy capture device based on vertical train vibration is designed for low-frequency rail vibration characteristics,which is derived by Hamilton variational principle,and a distributed parameter model of piezoelectric single crystal cantilever beam is established by combining piezoelectric constitutive equation and Euler-Bernoulli beam theory.The output power of the trap is greatly increased by piezoelectric structure optimization and magnetic repulsion gap optimization.The dynamic response characteristics of the trap under harmonic excitation are numerically analyzed by Runge-Kutta method.In addition,grid-like fluorescent film warning structure and energy collection-drive circuit based on LTC3588-1 energy collection and management chip are designed according to the actual operation of the train.Based on the above theoretical research,a prototype of the trap is designed and fabricated,and a test system is built.The relationship between the distance,frequency and open-circuit voltage of the two piezoelectric collectors is further discussed,and the influence of different loads on the output power is studied.In addition,the mechanism enhances 64.73% compared with the traditional energy gathering mechanism,which verifies that when there are multiple power generating locations in the whole system,multiple generators in the same system can show better energy collection effect than the single generator.Finally,the process of powering the warning device using the dual-voltage electromagnetic coupling energy capture device is demonstrated.The illumination of the warning device decreases from 0.83 LUX to 0.23 LUX within 10 minutes and recovers quickly after power supply.Taking 20 minutes as cycle time,the device can work continuously for more than 8 hours.This strongly indicates that the energy collector is expected to be applied in the new generation of train warning equipment to solve the power supply difficulties of train safety equipment.