The document presents a presentation on dynamic modeling of DC motor drives. It discusses different types of DC drives including single phase, three phase, and DC-DC converter drives. It also provides the generalized electrical diagram and dynamic model of a DC motor, describing the stator inductance and resistance, and how the electrical equation for a DC motor can be derived using Laplace transforms. The dynamic model expresses the stator current as a function of the stator gain and time constant.

1. Presentation
on
“Dynamic modelling of dc motor
drive”
ELECTRIC DRIVES

2.  Introduction
 Types of Drive
 Generalized electrical diagram
 Dynamic model of dc motor

3. • Direct current (dc) motors have variable characteristics and are
used extensively in variable-speed drives.
• DC motors can provide a high starting torque and it is also
possible to obtain speed control over a wide range.
• The methods of speed control are normally simpler and less
expensive than those of AC drives.
• Both series and separately excited DC motors are normally used
in variable-speed drives, but series motors are traditionally
employed for traction applications.
• Due to commutator, DC motors are not suitable for very high
speed applications and require more maintenance than do AC
motors.

4. • With the recent advancements in power conversions, control
techniques, and microcomputers, the ac motor drives are
becoming increasingly competitive with DC motor drives.
• Controlled rectifiers are generally used for the speed control of dc
motors.
• DC drives can be classified, in general, into three types:
– 1. Single-phase drives
– 2. Three-phase drives
– 3. DC-DC converter drives

5.  When supply is given to the stator winding of dc motor ,a flux
produced in stator winding which is linked to the rotor winding &
rotor starts rotating.
 Let consider a single coil stator having inductance Ls & resistance
Rs.
 Then electrical equation for dc motor is given as
 Where is is current flowing through the stator, and Vs be the
generated voltage. By using Laplace transform.

6. is called the stator gain and
is called as the stator time constant