Where is regenerative braking used and where dynamic braking? I am quite confused about this. How is block diagram for both. Which one has more advantage and which one is widely used?
I suggest you to take a look on the worldwide web there is couple of good explained video on this subject.
I post here a link on one of them to have a good and clear idea of braking generation, and dynamic braking: Electrical Braking Types [Animated] | Regenerative, Dynamic & Plugging for Drives
Lets tell me what's your thinking on ...
Dynamic braking is used on the applications where the deceleration speed varies, such as fans, where energy needs to be dissipated periodically. Regeneration is generally preferred when the motor is frequently acting as a generator.
Applications that involve frequent starts and stops, constant deceleration include downhill conveyors, elevators, flywheels, crane, hoist and elevator applications, where when the load is descending, the motor turns into a generator of electrical energy.
As other respondents have stated, when a load is overhauling the motor produces current (becomes a generator). So when accelerating an inertial load, the motor will consume all the amps the drive will give it. when overhauling, the opposite is true. the motor produces a current that the drive must handle. the motor is now generating.
If occasional, for say, decelerating to a stop, then the drive will handle the current simply by switching the energy out to a resistor to burn it off as heat. The amount of energy and duration must be short enough for the resistor to handle.
For systems that generate energy for longer periods of time, or have a safety component, the excess energy can be switched back to the line. This is called line regeneration. It's basically a 2nd inverter that functions only to put the excess energy back on to the service line. Bonitron's website likely has some good reading material on this topic