Most of space-based hardware operates on solar panels composed of lots of photovoltaic cells connected in short series that produce around 28V; lots of these are connected in parallel to produce desired amperage.
Meanwhile, many devices - in particular, ion propulsion - requires very high voltages to operate. They use massive Power Processing Units to provide the desired voltages, producing a lot of heat and losing power in the process.
Would it be advantageous to use solar panels that connect lots and lots of solar cells in series, generating high voltage directly? (and similarly, connect thermocouples in RTG in series)? Stepping the voltage down for various electronics use should be at the very least similarly hard as stepping it up, and the devices that require high voltage could be supplied through a simple regulator, without need to step up the voltage by a factor of a couple thousands.