Bidirectional motor controlling

Discussion in 'General Electronics Chat' started by Slids, Mar 12, 2014.

  1. Slids

    Thread Starter New Member

    Mar 12, 2014
    hi. :) we are are designing PWM motor control using PIC16F877A. Our problem is that what type of capacitor including its capacitance should we use to by-pass to the motor so that the charge collected by the motor as a inductive load will not affect the HBridge when running bidirectionally.

    Any kind of help will truly and highly be appreciated. :)

    Thank you!
  2. Sensacell

    Senior Member

    Jun 19, 2012
    There must be a path for the inductive currents to flow, diodes are the standard way of handling this.

    Usually you don't want to place much capacitance across the output of an H-bridge, there should be 4 diodes included in the circuit across the switch elements, these clamp the inductive voltages to the supply. If you use power MOSFETS the diodes are inherent to the FET.

    Very small capacitors are sometimes placed across the motor terminals to suppress EMI generated by the brushes, but they are not meant to absorb inductive energy from the armature coils.