I am building a wireless three phase induction motor control using esp8266-12E to drive three triacs for each phase coupled via zero cross optically isolated triac driver moc3062. To provide a stable 3.3v power supply to esp, I have used the transformer based below circuit enter image description here

Issues faced:

  • Random MCU reset while switching on/off the induction motor.

  • MCU resets when an another induction motor connected to the same three phase power supply is switched On/off

I am a hobbyist and don't have very deep electronics design knowledge. I have tried adding reservoir capacitors/filter capacitors to the power supply circuit. It reduced the random reset issue but not completely. I believe the issue is with my power supply to MCU. In noisy industrial environment involving induction motor control, EMI noises and power surges seems to cause random MCU resets.

There seems a lot of power supply designs available out there.

  • linear regulated transformer based( not very efficient but it's not a requirement for my application and am currently using this method)

  • switching power supplies( will off the shelf modules like this will help to solve my issues? MeanWell PS05-5

  • capacitive/resistive transformerless power supply (limited current only. Not suitable for esp current requirements but I can consider using attiny85 without wireless requirement, if this method provides stable surge free and EMI free power)

Any easy to understand solution to solve this issue will be of great help to me. Thank you

  • \$\begingroup\$ Have you tried adding larger capacitors on the output - across C3? \$\endgroup\$ – Icy Aug 11 '16 at 14:09
  • \$\begingroup\$ @icy yes.. tried and played played around with different values... As I have said in the issue details, it did helped to reduce the MCU reset issue, but not completely. \$\endgroup\$ – ke7 Aug 12 '16 at 4:35
  • \$\begingroup\$ Do you have access to a simple linear regulator like a 78xx series one? Just about anything to put a (pre)regulator between your diode bridge output and your MCU power supply. From the schematic you are using, even a resistor between the 1000uF capacitor and adding another bulk capacitor could improve the rejection of AC line supply noise. \$\endgroup\$ – user2943160 Aug 13 '16 at 0:47

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