Practical way to generate 1500V?
Use a cascade.

There are two main choices

a) Villiard aka Cockcroft-Walton aka Greinacher multiplier

Each stage is stacked on the previous stage, so capacitors and diodes only need to be rated at the input voltage, not the output voltage. However the output impedance increases as the number of stages squared.

b) Dickson multiplier

Each stage returns its pump and storage capacitors to ground, so capacitors need to be rated for the output voltage. However the output impedance increases only as the number of stages, so it can use smaller values of capacitance for the same output impedance as the other cascade.

Given a specification for output voltage, output current, and output impedance, you would need to fully design one of each type to determine which will give you the best cost or volume. Very high voltages would naturally favour type (a), but with only 1500V, both types are contenders.