I took Power Electronics Laboratory (EE462L/EE394-7) course during Fall 2021 and long story short, I enjoyed it immensely. While dealing with circuits operating at few 10s of watts, I never really fussed a lot about efficiency but once that power starts to go up, efficiency becomes paramount (not just to minimize energy wasted but that wasted energy often manifests as heat, how do we now dissipate it safely?). In this context I studied and built various circuits for AC-DC rectification (Diode Bridge rectifier), DC-DC converter (Buck, Boost and SEPIC) and finally DC-AC inverter (H-Bridge). I already utilized the AC-DC diode bridge rectifier for powering my Solder Reflow Oven 2.0, so suffice to say that the knowledge I acquired during this course has already been put to good use.
One of the most interesting aspects of this course was the H-Bridge Inverter design challenge. The challenge was based on optimizing along two thrusts, the first thrust focused on maximizing the efficiency of the inverter and the second thrust was concerned with minimizing the bill of materials (BOM). We were tasked with selecting the power MOSFETs which were a part of the phase legs of the inverter and in designing the boostrap circuitry required to provide a floating voltage source to drive the high-side MOSFETs in each phase leg.
My design achieved the 2nd highest efficiency in the history of the course and I will discuss how I went about modelling the circuit to choose the appropriate components.
Figure 1 : H-Bridge Inverter board
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What is an Inverter
An inverter is a device that changes a DC input to an AC output.