How can a separately excited dc motor be controlled using a chopper?
The speed of Separately Excited DC motor is controlled to a maximum of its rated speed using chopper as a converter. The speed controller used is Proportional Integral type which reduces steady state error and provides fast control. The parameters of the speed controller have been designed using control system theory.
What are separately excited DC motors used for?
Separately excited DC motors are often used as actuators in trains and automotive traction applications. For their constant speed characteristics, shunt DC motors are used in fixed speed applications such as fans. square of armature current), they can be used in applications that require high starting torque.
How can you control the speed of a separately excited dc motor?
The speed of separately excited dc motor can be control by changing the armature voltage and changing field flux. Due to this the speed can be controlled for below rated speed and speed above the rated speed, respectively.
How does a separately excited dc motor is different from other motors?
Separately Excited DC Motor The main distinguishing fact in these types of DC motor is that, the armature current does not flow through the field windings, as the field winding is energized from a separate external source of DC current as shown in the figure beside.
Can we use regenerative braking in DC series motor?
Why? In case of DC Series motor, as the speed of Motor increases, the armature current and hence the field flux will decrease and therefore Back emf E can never be greater than the supply voltage V. Therefore, Regenerative Braking is not possible in DC Series Motor.
Why is chopper control of separately excited DC motor important?
The most important feature of chopper control is that the regenerative braking is carried out at very low generating speed when the drive is fed from a fixed voltage to low DC voltage. The transistor chopper controlled separately excited DC motor is shown in the figure below.
How are the control loops in a DC motor used?
There are two control loops, one for controlling current and another for speed. The controller used is Proportional-Integral type which removes the delay and provides fast control. Modeling of separately excited DC motor is done.
What kind of circuit is used in a chopper?
The chopper converts the fixed DC voltage to variable DC voltage. Self-commutated devices (directly on or off devices via gate) like MOSFET, IGBT, power transistors, GTO and IGCT are used for making choppers because they can be commutated by low power control signal and do not need commutation circuit.
How to design a DC motor drive system?
CHAPTER: 4 MODELING OF DC MOTOR FOR DRIVE SYSTEM 21 4 . 1 B a s i c 2 I d e a 2 2 4 . 2 M o d e l i n g 5.1 o f S e p a r a t e l y E x c i t e d D C m o t o r 2 3 4.1 Basic Idea 22 4.2 Modeling of Separately Excited DC motor 3 CHAPTER: 5 CONTROLLER DESIGN 28 Controller Fundamentals 5.2 Deciding Type Of Controller