A study on the optimal design and the performance evaluation of electromagnetic energy harvesting device for the rolling stock application

Abstract

An electromagnetic energy harvesting device was studied based on the design parameters of an energy harvesting device for the power source of wireless sensors node on the rolling stock. The characteristics of the generated power by the energy harvesting device were tested using the laboratory equipment and a rolling stock (a high-speed train). First, a cantilever beam energy harvesting device, which allows for easy adjustment of the length according to the frequency and the power according to the cantilever beam materials, was researched. In addition, the new design for a practical resonant energy harvesting device for the railroad system was performed. To realize the performance of the practical resonant energy harvesting device, the generated power characteristics of the energy harvesting device were tested according to the moving displacement, the number of coil turns, and the initial coil displacement between the coil and magnet. The evaluation of the performance of the manufactured resonant energy harvesting device for the railroad system, which the parameters were determined based on the test results, was conducted under real driving conditions in the high-speed train, which was traveling at 300 km/h. Finally, this study analyzed whether the power generated could be applied to the wireless sensor nodes for the railroad system.

A Study on the Energy-Harvesting Device with a Magnetic Spring for Improved Durability in High-Speed Trains

“…A previous study verified the applicability of metal spring VEH devices in producing electric energy from a vibration energy source based on the operation of a high-speed train [ 1 , 5 , 41 ]. The metal spring VEH device was designed so that the same neodymium (Nd) magnets (outer diameter, 25 mm; inner diameter, 10 mm; thickness, 7 mm) were arranged in pairs, and two coils were arranged similarly to correspond to each upper and lower magnet, as illustrated in Figure 1 [ 5 ]. The Nd magnet was selected Grade N30AH (the maximum operating temperature of up to 230 degrees Celsius) for the high temperature of VEH device’s inside near the axle box, which is a high-temperature place on the bogie during the high-speed train operation.…”

“…A number of experimental studies have been conducted to investigate the energyharvesting power of VEH devices based on various design factors to verify the applicability of energy-harvesting technology that produces electrical energy from vibrational energy under testbed conditions [16,[45][46][47][48]. A previous study verified the applicability of metal spring VEH devices in producing electric energy from a vibration energy source based on the operation of a high-speed train [1,5,41]. The metal spring VEH device was designed so that the same neodymium (Nd) magnets (outer diameter, 25 mm; inner diameter, 10 mm; thickness, 7 mm) were arranged in pairs, and two coils were arranged similarly to correspond to each upper and lower magnet, as illustrated in Figure 1 [5].…”

“…The maximum generated RMS voltage of the lo dition (Vrms-veh) was measured by connecting a 360-Ω load re coil's 368-Ω internal resistance in the lower coil of the magne used for convenient testing using the load resistance. The ex ated power (Pexp-veh) was calculated using Equation ( 1) with the generated voltage (Vrms-veh) and the load resistance (R) [5, was used to calculate the average pow to the load (i.e., the power dissipated across the load resistan The results of measuring the generated voltage accord tion are presented in Figure 11a-d. The resonance frequency VEH device was predicted to be 44 to 45 Hz in the design sta the resonance frequency at the maximum generated voltage acceleration of 0.5 G, which was very close to the predicted design of the magnetic spring VEH device.…”

“…However, the need for a continuous power supply remains a challenge [ 3 ], and an extended power supply for wireless sensor nodes is required for alternative energy sources, such as energy-harvesting technology. The power supply can be increased by utilizing existing environmental energy sources [ 4 , 5 ]. Among the different environmental energy sources, vibration energy exists in various systems and structures and has attracted attention as an energy source that can be harvested [ 6 , 7 ].…”

“…An analytical estimation study was conducted on the energy harvested from the high-speed train’s vibration acceleration based on a theoretical model [ 1 ]. A design study was also conducted to investigate the potential energy-harvesting power considering the VEH device’s design factors, and a new design for the VEH device was proposed [ 5 ]. However, durability is a critical issue in the implementation of a VEH device in a high-speed train.…”