Design And Experimental Of A Gyromagnetic Piezoelectric Cantilever Generator For RWMS

In recent years, our high-speed railway has made rapid development, the increasingspeed also brings a certain influence on the stability and comfort of the trains, and as well asthe safety and reliability between the wheel bearings and other components. For this reason, avariety of railway wheelset monitoring system (RWMS) are developed. However, the existingfreight trains have no power supply systems, passenger cars need regular marshalling and theinconvenience of wire power supply, battery power supply affords short duration and requireschange frequently, thus severely restricting the promotion and practical application of railwaywheelset monitoring technology. Therefore, generators with a set of integrated monitoringsystems can continue to power seem imperative. Using piezoelectric vibration energyharvester for micro-power electronics and micro-power remote-sensing monitoring systemshas become a hot topic in many fields in recent years. This thesis proposes a new method byusing a gyromagnetic piezoelectric generator (GPG) for the RWMS based on analyzing thecurrent technological developments and its application, proving the feasibility of RWMS. Theinfluence of magnetic force (number and configuration of the magnets) and rotating speed ondynamic characteristics and energy generation of the GPG is investigated theoretically andexperimentally. Details are as follows.According to the form of piezo-cantilever’s structure, this chapter analyzes the vibrationtheory of piezo-cantilever through the theory of Euler-Bernoulli beam, establishes adifferential vibration equation of the piezo-cantilever, and discusses the generatingperformance theoretically.Then the thesis establishes a theoretical model of a piezoelectric vibratory energyharvester and carries on numerical simulation analysis. To obtain the influence of rotatingspeed of magnet, duration of exciting and period-ratio (duration of exciting to exciting period)on the response performance of pizeo-cantilever (waveform and amplification factor), adynamic response model for the piezo-cantilever under magnetic impact force is establishedand simulated. Besides, the effective speed-band for real-time self-powering can be enhancedwith increasing magnetic force or the number of piezo-cantilevers with different naturalfrequencies. And the influence of coupling excitation amplitude and excitation frequencybetween moving magnet and fixed magnet during different clearances and distance ration isdiscussed, as well as the influence of its coupling characteristics.At last, the thesis designs a GPG and carries on a test. The thesis obtains the influencerules of the scale, mass, the number of the piezoelectric, the pole configuration mode and therelative position of the excited and exciting magnets in different rotational speed, whichproves the correctness of the theoretical analysis. At the same time, the thesis studies the characteristics of serial-connected piezodiscs with different output mode and obtains theinfluence of a variety output ways, such as the direct serial/parallel, on the voltage andbandwidth.