Hi,
Power supply is a wide range.
I recommend to refine what you are really interested in.
There are usual AC DC power supplies for elelctronics. Maybe up to 60V and up to 10A. But even here is a wide bandwidth. They may be used for testing, so they need to be variable in voltage and current. Single or symmetrical. Linear or switched mode. low noise, high power, high efficiency ...
There are low power capacitive ones
But there are power supplies for lasers, with very narrow pulse widths, still high power.
There are power supplies for medical use, where you need special care about safety and leakage currents.
There are industrial high power ones for chemical processes (I´ve build some up to 1MW).
There are AC AC power supplies ... maybe one or more phases, maybe variable frequency ....
There are DC DC power supplies, isolated or not..
And there are the rules and regulations. I already mentioned safety, but there also is EMI/EMC and so on.
***
Because this field is so huge, I can not recommend to study all at once.
For each single use case you will find books, but usually every simiconductor manufacturer gives informations in Appication notes and design notes. They tell you what to care for and how to calculate them part values. And how to do PCB layout (GND plane, trace widths, trace lengths, inductance, sensing techniques, heat spreading ...)
Klaus