Virtual On line
June 22, 2020
June 22, 2020
June 26, 2021
Electrical and Computer
Wireless power transfer is an emerging field and promises to become a necessity in the future with the emergence of electric vehicles and increasing renewable energy generation. In this paper, we present an interactive activity for teaching the engineering design and electrical engineering concepts to high school students. The activity is designed to educate the high school students with fundamental principles of WPT: inductor design and magnetic coupling, and to provide them hands-on experience with wireless charging.
The activity is divided into three steps: (i) designing and making an Rx coil (ii) parking an RC car with student-made Rx coil underneath a fixed charging station where the Tx coil is located (iii) racing the charged car to compare the charging performance by measuring the distance covered by the cars.
WPT using magnetic induction requires two coupled inductor coils, the transmitter (Tx) and receiver (Rx) coil. To ensure successful power transfer across a variety of student-designed receiver coils, the activity uses carefully designed resonant circuits at both transmitter and receiver end. The WPT coils and the corresponding resonating capacitors significantly improve the performance over the non-resonant inductive WPT.
To simplify the activity yet keep it effective, we provided the students with a resonating Tx station and an Rx compensating circuit and tasked them with designing receiver inductor coils. The students have a range of choices for parameters including the number of turns, and the dimensions of the receiver coil inductor, with each choice determining the performance of the WPT system.
The students, then park an RC car with their receiver coils underneath a given Tx station to ultra-capacitor bank storage of the car wirelessly. By learning to park the RC car underneath the transmitter station, the students gained an intuition of the mutual flux linkage, hence the mutual coupling between Tx and Rx coils. The evaluation of their designs and parking was done by driving the RC cars until exhaustion of the electric storage. The closer the inductance of the Rx coil to the provided specifications, the better the performance of the charging system. With the alignment of the Tx and Rx coil further playing part in determining the distance covered by the cars.
We conducted the activity with 24 high school students in a summer camp at the University. The background of the students was tested using an informal quiz at the beginning: 3 of 24 students (12.5%) had some knowledge about inductors and 7 of 24 (29 %) knew about alternating voltages and currents. After the activity, to evaluate what the students had learned, we had the students take a written test. This evaluation showed that 96% of the students had developed an intuition for inductor design, and 62.5% of the students were able to correctly identify the concept for magnetic coupling including proper alignment, the distance between two coils and the relative size of Rx coil with respect to the Tx coil. The students gave an average rating of 8.2/10 for how much they liked the competition, further indicating their engagement in the activity.
Sarin, A., & Chu, S. Y., & Hofmann, H., & Avestruz, A. (2020, June), Charge Up! Wireless Power Transfer Activity for High School Students Paper presented at 2020 ASEE Virtual Annual Conference Content Access, Virtual On line . 10.18260/1-2--34277
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