Design And Experimental Research Of A Rotary Circular Piezodisc Energy Generator Excitied By Magnets

The piezoelectric energy generator is used to convert mechanical energy into electrical energy by piezoelectric effect. Compared to other kinds of energy harvesters, its structure is simple and various, does not hot in the working process, no electromagnetic interference, no environment pollution, it also has the advantages of easier to implement miniaturization and integration, and high energy density, etc. In order to meet the requirements of the self-powered sensor monitoring system of rotating machineries, such as helicopter propeller, TPMS, spindle of high-speed train, etc, a novel rotary circular piezodisc energy generator excited by magnets is presented in this paper. The performance of the piezoelectric generator was investigated theoretically and experimentally. The specific contents of this paper are as follows:1. Analysis of the research status and application examples of the piezoelectric energy generator overseas and domestic, and analysis of the deficiencies of the piezoelectric energy generator existing currently. For the deficiencies of vibration noise and low reliability and so on, and the requirements of the self-powered sensor monitoring system of rotating machinery, a none contact incentive and axial bending vibration rotary circular piezodisc energy generator excited by magnets was presented.2. The performance parameters and supporting mode of the piezoelectric vibrator were analyzed. For rectangular and circular piezoelectric vibrator, modal analysises were carried out and the displacement for the simply supported and clamped piezoelectric vibrator were analyzed by using the finite element software, the structure form of the piezoelectric vibrator was determined, namely clamped circular piezodisc, and the influence of the structure parameters of circular piezodisc on the base frequency were researched.3. The basic structure, working principle of the magnetic excitation rotary generator were analyzed, getting the key factors that influence the output performance, the mathematical model of the generator was established. Exciting force produced by the exciting magnets was tested in the horizontal and circumferential direction, including attraction, repulsive, and interval incentive methods, respectively. The influence rules of gap ratio, distance ratio and angle ratio on the exciting force were found, respectively. Using the numerical simulation software, the influence rules of period ratio, load time, rotating speed, and mass on the displacement response of the piezodisc were found, respectively. The displacement response of the piezodisc could be the characterization of the output voltage.4. A rotary circular piezodisc generator excited by magnets was designed and manufactured, and a test system was build. The influence rules of exciting magnets number, exciting frequency and method, the total mass of peizodisc, and rotating radius on the output performance of the piezoelectric energy generator were achieved by a single magnet excitation, respectively. The time domain response of the generator was analyzed. For better understanding on the output performance of the energy generator. the experiment test exciting by combinative magnets were studied, and the influence rules of each group exciting magnet number and rotating speed on the output performance of generator were found, and take use of the energy coefficient to characterize the output electrical energy.Summing up the above analysis, the rotary circular piezodisc energy generator presented in this paper has the advantages of non-contact excitation, small vibration noise, strongly ability to adapt to the rotating speed. In addition, axial bending deformation of piezoelectric vibrator results in the high reliability. Through analysis of the test results, the feasibility of the scheme was proved, and it provided a reference for rotary piezoelectric energy generator for further study.