12V, 150W => more than 10amps!
what size of wires do you use for power supply , and especially for ground wich is common for MCU and Motors?
Add also big capacitor accross the lipo battery output .. to reduce the noise on the power supply.
Add also a 100µH inductor on the input line of LM2576 3,3V...
For noisy environment, maybe the use of a linear voltage regulator is better than a switcher regulator ,
wich can be disturbed when using big power PWM for motors..
even efficency is less.