I drive a BLDC motor with an ESC. When using power from a LiPo battery everything works as expected. When I use a power supply, on rapid stops or slowdowns motor generates voltage spikes, which send my ESC to overvoltage protection.

How can I deal with it? Will a zener diode work with PSU, if it's voltage rating will be higher than PS voltage and power rating enough for heat dissipation?

May be there is another way to do it correctly?


Additional info: With oscilloscope I am unable to catch spikes on power input, no spikes there. They only show up on motor phase lines. I see PWM signal. I can catch higher voltage than usual there when braking or slowing down.

I have 1300 uF capacitance on the ESC. I use T-Motor MN5212 and 18 inch propeller.

Wires from the PSU to ESC are 10 cm.

Tried without the prop, same result.

  • \$\begingroup\$ Comments are not for extended discussion; this conversation has been moved to chat. \$\endgroup\$ – Dave Tweed Apr 8 '17 at 22:22

First ad a large capacitor or bank of more capacitors. The zener will probably burn out very quick because of large amount of kinetic energy that is converted back in electricity. Your device needs to absorb the total amount of the energy generated during quick deceleration. Usually such device exists in servo drives named as braking resistor. This resistor is switched on by help of the MOSFET when the voltage rises above a defined threshold and it is switched off when the voltage drops below the threshold with a hysteresis. If the capacitor bank has enough capacitance then the voltage rise will be smaller.


In a H bridge drive to motor, mechanical or stored inductive energy is released into the power rails because of the presence of diodes, actual or parasitic (in the case of MOSFETs).

This means the power rail can rise but a battery close to the circuit will keep it in check. If the battery is too far away, the inductance of the cable can facilitate spikes and this is also a problem. So, try shortening the power supply wires or twisting them together and this may give an improvement. If the improvement is not good enough then, add power supply capacitors across the H bridge.


Use big Ferrite noise absorbing CM chokes or U-clamps or clamshells. Its a must for all industrial stepper motors too. then do same for ESC cable and add shield TP (grounded at source end) only if necessary.

Also evaluate DCR of motor and make Decoupling caps ESR 1% of DCR and use Sch. power diode clamps at source to both rails as std for inductive switched loads.

Make sure motor power + ground path is not shared by CPU or ESC drivers.

The purpose here is the raise the CM impedance so current is reduced in magnetic current coupling from antenna effects. For E Field noise voltage use RF caps on ESC cable to gnd (xx pF) or series Ferrite donuts equivalent to 100 pF load in noise reduction. schematic

using twisted pair helps EMI too to reduce differential noise.

if you use Torrids wrap as many turns of wire pair as possible thru torrid. If large cable use Clamshell types (snap-on)


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.