Closed Loop System

Closed Loop System

1. Improved accuracy2. Fast dynamic response3. Reduced effects of load disturbance and system nonlenearities

ADVANTAGES

Open Loop Transfer Function

PLANT ? GAIN ?

Open Loop Transfer Function

Open Loop Transfer Function

LAPLACE TRANSFORM??

ARMATURE CURRENT

MOTOR SPEED

Open Loop Transfer Function

ARMATURE CURRENT MOTOR SPEED

Torque

Speed

MaximumTorque

By Changing Armature voltage

Trated

Va increasing

Open Loop Transfer Function

Response due to step change in references voltage is obtained by setting TL to zero ;

Open Loop Transfer Function

Response due to a change in load torque TL can be obtained by setting Vr to zero ;

Final Value Theorem ; steady state relationship of change in speed due to step change in control voltage and step change in load Torque (s=0)

Closed Loop Transfer Function

Closed Loop Transfer Function

Closed Loop Transfer Function

Final Value Theorem ; ( with feedback gain K1 )

Closed Loop Speed Control Examples• Inner current loop and field weakening

Closed Loop Speed Control Examples• DC-DC converter-fed speed and position control system with IGBT bridge

Exercise

Exercise ( Solution )

Exercise ( Solution )

Exercise ( Solution )

Assignment 4

• In your own words, discuss the system operation by describing the function of each operation block and current flow in not less than 1 page. ( group assignment )