I saw the word "shunts" in this answer about DSCOVR's upgraded photovoltaic arrays when it was unmothballed and readied for space. Reading it, I get the idea that shunts are used to dissipate the difference in power between what the satellite needs and what the array is producing.
In this answer which is actually about silicon PVs on the ISS, it is mentioned that when entire arrays are offline, they get hotter, and I'm assuming this is because they are left open-circuit and so all the electron-hole carriers remain in the junction and recombine, returning their energy as heat.
And I'm also wondering that if you need less than the full amount of energy, if you had a modern switching power supply to condition the voltage, wouldn't you just draw less current, instead of full current and shunting some into a big hot resistor?
So to narrow the question down I should ask about modern designs and recently built and launched satellites. I'm thinking communications satellites, but since DSCOVR received a modernized system, that's OK too. Of course if there is something more compelling, that's fine, but the ISS can be a separate question because there are issues of legacy and compatibility.