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Applying Variable-Switching-Frequency Variable-Phase-Shift Control and E-Mode GaN HEMTs to an Indirect Matrix Converter-Based EV Battery Charger
No full textAn indirect matrix converter is employed directly converting the grid ac to the battery voltage, with the dual-active-bridge taking care of the power factor correction and power delivery simultaneously. Such circuit is regarded as one candidate of the high-efficiency and high-power-density electric vehicle onboard chargers, if the double-frequency current ripple to the battery is tolerated. Instead of optimizing the overall charger, this paper is focused on adopting variable switching frequency with multiple phase shifts to accommodate the wide input range (80-260 V ac ) and output range (200 V-450 V dc ). In addition to the phase shift between the transformer primary-side and secondary-side voltage, one extra phase shift is added to the primary-side H-bridge when the instantaneous input voltage is higher than the reflected output, otherwise, to the secondary side. The goal is to secure zero-voltage-switching for all switches at all voltage range. Such control strategy is further optimized incorporating with the switch parasitic capacitance and deadband settings. To further enhance the charger performance, GaN HEMTs are equipped to the on-board charger aiming at higher efficiency and higher power density than Si devices. Experimental results indicated that such charger with proposed control strategy embraces the peak efficiency of \u3e97% at 7.2 kW and a power density of ~4 kW/L
Fostering an Entrepreneurial Mindset in Digital Systems Class through a Jigsaw-puzzle Model
No full textIn this paper we introduce a jigsaw-puzzle model to instill an entrepreneurial mindset in students. We then use our model to craft and add innovative lab assignments to “Digital Systems”, which is a core course taken by Electrical Engineering, Computer Engineering and Computer Science students worldwide. In each lab assignment, students are provided with some components or puzzle pieces as well as the user guide of a digital system, and possibly some reading materials to better understand the operation theory of the system. One selling point of our model is its significant flexibility, so that the game may be played in different ways. Here is one example: students go over the user guide and the reading materials to get a solid understating of the underlying digital system. To comprehend what they have available, students also study the puzzle pieces. Then students challenge themselves to complete the puzzle and eventually build the digital system physically and test it. The resulting system is supposed to function in accordance with its user guide. Our work is an attempt to fulfill the Kern Entrepreneurial Engineering Network (KEEN) Students Outcomes. The anonymous survey from the students is encouraging and shows that our work is able to excite students\u27 curiosity, provide them with an opportunity to apply creative thinking, and instill in students a feeling of value creation among other things
Advanced Energy Storage Technologies and Their Applications (AESA2017)
Get PDFThis editorial summarizes the performance of the special issue entitled Advanced Energy Storage Technologies and Applications (AESA), which is published in MDPI’s Energies journal in 2017. The special issue includes a total of 22 papers from four countries. Lithium-ion battery, electric vehicle, and energy storage were the topics attracting the most attentions. New methods have been proposed with very sound results
