DC Brake Function by VFD in induction motor

DC Brake function is most commonly used to hold the induction motor in stand still position. Will not truly lock the rotor thus cannot replace for example mechanical brake in lifting applications. In horizontal movement it is often good enough for holding the mechanical system still for short period of time. Keep in mind the induction motor without forced cooling will heat up.
Other place where DC injection is used is for example lifting application to secure the appropriate magnetization of the motor before releasing mechanical brake. Without premagnetization of the motor, the remanent flux may result to inadequate torque and causing rotor not to follow the "new flux" immediately. This may cause dropping of load in lifting applications when opening the mechanical brake. Using DC injection will allow the variable frequency drive to know what the actual flux in motor is when starting to generate torque by introducing frequency to the stator.

High performance variable frequency drive makes a measurement of the torque through the current to control the brake, for other it's based on speed reference. Then it depend the brake to stand still the motor or decelerate the motor and stop him. When using a DC brake always clearly define what you want to do (stand still or decelerate), then if it's a safety material, then check drive control type.

There is also the possibility of regenerative breaking to the DC bridge of the VFD and using a break resistor to brake the motor. This is possible with a variable frequency drive that has brake resistor connections (brake chopper circuit). These are to be used if the DC brake is not sufficient to stop the load for example in an e-stop situation.

Also an active front end (or some call it an active rectifier module) could be used to dump the regenerated energy from the generating motor in its braking condition as the system would become a regenerative 4 quadrant with the added reverse rectification element. This would also help out with the site harmonics and power correction if the drive is large.