We have a brushless motor with the following characteristics (Slow(8T)): enter image description here

For that motor, we are developing an electronic speed controller using the hall sensors. The microcontroller is an atmega328p and we are generating a PWM frequency of 8kHz in the low MOSFETs with a 6-step commutation.

The problem is that this configuration generates high currents (4 A in the source and 10 A in each phase) and in a short time of motor operation, the MOSFETS start to heat up.

I would like to know if the problem is in the design of the controller, the frequency of the PWM, or something that we are not considering to improve the performance of the controller.

Here is the schematic: enter image description here

enter image description here

enter image description here

How can I improve the design of my electronic speed controller?

  • 1
    \$\begingroup\$ Are you sure that you do not have "shoot-through" which occurs if both top and bottom MOSFET are on at the same time? \$\endgroup\$
    – Transistor
    Feb 3 at 18:59
  • \$\begingroup\$ Which Gate driver ICs are you using? What is the motor supply voltage? Do you have an oscilloscope? \$\endgroup\$ Feb 3 at 19:23
  • 2
    \$\begingroup\$ May not be related but I wouldn't be using such slow diodes in the driver bootstrap circuit. \$\endgroup\$ Feb 3 at 20:07
  • 1
    \$\begingroup\$ @evildemonic The MOSFETS are IRFZ44N AND the gate drivers are IR2110. The resistor value was chosen arbitrarily, if you have some advice to choose it correctly I would appreciate it. Here are the datasheets of the MOSFETS and gate drivers. Thanks. MOSFETS: pdf1.alldatasheet.com/datasheet-pdf/view/68619/IRF/IRFZ44N.html DRIVERS: pdf1.alldatasheet.com/datasheet-pdf/view/323402/IRF/IR2110.html \$\endgroup\$ Feb 5 at 22:22
  • 1
    \$\begingroup\$ For a simple shoot through test, try running the motor controller without the motor attached. If there isn't any shoot through the supply current drawn will be quite low. The turn on/off characteristics of the FETs will be a little different B/C there's no load current but bad shoot through conditions will be easy to spot and troubleshoot. All you need is a multi meter or a bench power supply with a current meter. \$\endgroup\$ Feb 19 at 6:49

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