I have a five 12 V DC motors and I want to use an SMPS instead of lithium battery
Yes of course.
It's not that easy though finding an SMPS that is able to deliver to the motors a steady current of 15 A steadily and and istantaneous current of 150 A.
The SMPS output voltage must remain stable under any working condition.
That means that you should provide a fairly big capacitance at the input and output of the SMPS in order to fulfill the current peak requests of the motor.
You might also want to pick an SMPS which works at a frequency higher than 250 KHz.
You might want to pick a multi-phase buck converter like:
https://www.ti.com/product/TPS53679
https://www.ti.com/lit/an/slva882a/slva882a.pdf?ts=1616002070641&amp;ref_url=https%253A%252F%252Fwww.google.com%252F