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Universal Battery Supercharger
thesisposted on 01.08.2021, 00:00 by Nikhil Kumar
In this dissertation, a universal battery supercharger (UBS) is presented that is based on a differential-mode-Cuk-rectifier (DMCR) topology. The UBS is targeted for DC fast charging application to reduce the range anxiety among the EV users. To fully understand the UBS (DMCR) topology, a comprehensive analysis of the high frequency and low frequency operating modes using an existing discontinues modulation scheme have been discussed in detail. However, due to presence of passives, the DMCR topology is prone to resonance frequency oscillations that makes the converter control complex and challenging. To mitigate this drawback two approaches; passive damping and multiloop control schemes are analyzed and experimentally validated. A scaled power UBS (sp-UBS) is designed to test the closed-loop control scheme and to parametric performance comparison between discrete magnetics and integrated magnetics. Finally, to extend the sp-UBS to 60-kW UBS, a pathway is through identifying critical components. To test the HCPCB design, SiC modules, integrated magnetics, a 20-kW UBS module was designed. Based on a preliminary CAD model, three such 20-kW UBS modules were integrated together to form a 60-kW UBS. Gradually, as power is increased on the 60- kW UBS prototype, several challenges were faced, and resolved. Steady-state and transient characterization results along with the parametric results are provided in detail.