Application of single dc motor in series and separately excited mode

1. APPLICATION OF SINGLE DC MOTOR IN
SERIES AND SEPERATELY EXCITED
MODE
Somu Gupta
Electrical and Electronics Engineering

2. INTRODUCTION
 An electric car is a plug-in electric automobile that is propelled by one
or more electric motors, using energy typically stored in rechargeable
batteries.
 An innovative technique is proposed to run a DC series motor and
converting it into DC separately excited as and when required to do
regenerative braking and controlling a loaded car.

3. DESCRIPTION
 To control the car we need to control the motor for which we will use a
motor controller or drive which will be used to do regenerative braking,
controlling speed of the car and also to start and stop the car.
 To run the car we need a high starting torque for which dc series motor is
most suitable but for regenerative braking we need a separately excited
DC motor
 In this technique we proposed to connect the dc series motor with a
microcontroller and an another field coil and connecting this in such a way
that we will start and run our motor with dc series and set a speed limit
crossing which microcontroller will automatically cut series winding and in
very short time i.e. in seconds connect separately excited field winding in
running conditions at same parameters thus making it separately excited
and vice versa.

4. BLOCK DIAGRAM
Battery Bank Motor
Controller
DC Motor Potentiometer Break Wheel
Series to
separately
excited
Separately
excited to
series
Velocity sensor
circuit
Microcontroller

5. MOTOR SWITCHING
In the motor switching we are taking a DC motor circuit apparatus comprising
of two field coils and an auxiliary battery and microcontroller switching circuit
with digital speedometer and analyser circuit in this apparatus we will connect
according to the given circuit diagram .
M
Microcontroller
Battery
Auxiliary
Battery
Analyzer Circuit
circuit diagram for motor switching

6. SIMULATION MODEL
curve

7. SPEED TORQUE CHARACTERISTIC

8. ADVANTAGES
 To get a high starting torque.
 To do regenerative braking.
 To get an auxiliary Battery charged by regenerative braking for emergency use.
 It helps in improving the vehicle efficiency.
 It also proves to be economical and easier to use where both series and separately
excited motor needs to be worked for completing a single job under given conditions.

9. CONDITION OF OPERATION
 We use the single motor for all three purposes i.e. DC Series, Separately Excited and as well
as for Regenerative breaking.
 We change the motor without affecting external inertia which is due to the weight of the
car.
 This inertia we assumed that will be providing the flux continuity to both of the working
condition.
 If the motor is running at constant speed and is in the separately excited mode then small
intervals of not accelerating i.e. not breaking mechanically or manually, will be providing
the regenerative braking.

10. FUTURE SCOPE
 Widely and commercially acceptable.
 It is very safe.
 It may eliminate many problems Such as power losses.
 The dual purpose application may be used for other applications in
industry as it is saving one complete motor.