Protection for microcontroller from EMP

[stoyanoff]

Hi! I have a microcontroller controlling a small threephase 300W engine through frequency inverter. Here is the problem. When the engine is not connected to the chart everything works fine. But when I connect the engine in the moment when the engine starts my controller resets. After a few restarts the controller starts but it doesn`t work correct. My power supply modul has 2 electrolite caps(1000uF) and 7805 regulator(1 cap after and 1 before it). I have 100uF electrolite and 100nF nonelectrolite caps nearby the controller.
What else can I do to stop this???
Thanks!

 

[HTA]

Hi,

Looks like the microcontroller gets a supply interruption from the inrush current when the engine starts. If this is the case it would make sense to separate the supply and limit the inrush current, or add a separate power supply. An example for the analog/digital power supply separation you find here: **broken link removed**.

Enjoy your design work!