The document summarizes a presentation analyzing the performance of a DC motor with a DC-DC chopper fed power supply. It includes an introduction to DC motors and choppers. Simulation models of a DC motor with a simple DC voltage source and with a chopper-fed supply are created in MATLAB Simulink. The speed, current, torque and voltage waveforms are compared between the two models. While the chopper provides control of the motor speed, its output contains ripple which reduces performance compared to the simple DC source.

1. REC-CON-19
Rajkiya Engineering College
Ambedkar Nagar
Topic-Analysis of a DC Motor with DC to DC Chopper Fed Supply
Presented by-
Praveen kumar singh
B.Tech-4th year
Rajkiya Engineering College Bijnor

2. OUTLINE-
❖Introduction
❖DC MOTOR
❖DC TO DC CHOPPER
❖SIMULATION MODEL AND RESULT
❖Comparison
❖CONCLUSION
❖REFERENCES

3. Introduction-
➢Around 40 percent of the world’s power needs are currently met by electrical energy.
➢Electrical motor is a device that has brought about one of the biggest advancements in
the fields of engineering and technology.
➢Type of electrical motor is-
❖DC Motor
❖AC Motor
➢The various applications of DC motor are in Lathe Machines, Centrifugal Pumps, Fans,
Blowers, Conveyors, Lifts, Weaving Machine, Spinning machines, etc.
➢Power electronics is an umbrella term that encompasses the systems and products
involved in converting and controlling the flow of electrical energy.
➢ For the speed variation of DC shunt motor one of the method is armature voltage
control by chopper.
➢Simulation model of chopper fed DC shunt motor in MATLAB SIMULINK software is
presented.

4. DC motor-
➢
➢DC motors are very commonly used as variable speed drives and in
applications where severe torque variations occur.
➢Types of DC Motor-
❖Series Motors
❖Shunt Motors
❖Compound Motors
➢A DC shunt motor is a type of self-excited DC motor, and it is also known as a
shunt wound DC motor.
➢The DC shunt motor construction is the same as any type of DC motor.
➢This motor can be constructed with the basic parts like field windings
(stator), a commutator and an armature (rotor).
➢

5. DC-Shunt Motor WORKING AND Circuit Diagram-
➢The field windings is connected in parallel to the
armature winding.
➢When a DC motor is switched on, direct current flows
through the armature conductors and field windings.
➢This flow of current produces armature field and pole
field. Now, there are two magnetic fields in the air-
gap between field shoes and armature.
➢These two fields react with each other to rotate the
armature.
➢The commutator reverses the direction of flow of
armature current at regular intervals so that the
armature field is always repelled by pole field.

6. DC to DC Chopper-
➢A DC chopper is similar to an AC transformer because it behaves in
same manner.
➢The choppers are progressively proficient because they involve in one
stage conversion.
➢Based on output voltage Choppers are classified as-
❖Buck Converter
❖Boost Converter
❖Buck-Boost Converter
➢Buck-Boost converter is used for analysing the circuit.

7. Principle of operation of Buck-Boost converter-
➢Chopper is the application of varying the fixed dc voltage to the load.
➢This can be accomplished by continuously triggering ON and triggering
off the switch at high frequency.
➢The time duration for which the switch remains in ON and OFF states are
called ON time and OFF time respectively.
➢The ratio of on to off time is called mark to space ratio and the ratio of
on time to total time period of switch is called duty cycle(D).
➢By varying the duty cycle of switch the average voltage at output of
chopper can be varied.
➢Output voltage of buck boost converter is varied as per the formula
shown in equation 1.
❖V0 = D / (1-D). Vin

8. Simulation model of DC Motor with
simple DC voltage supply-
❖DC voltage source
Voltage=148V
❖Speed of DC machine
=1150 RPM

9. Simulation result (Output waveform)-

10. Simulation model of DC Motor with DC
TO DC CHOPPER FED supply-

11. SIMULATION RESULT(OUTPUT WAVEFORM)-

12. INPUT AND OUTPUT(FED TO MOTOR)
WAVEFORM OF CHOPPER-

13. Comparison-
➢When the DC Motor is fed from simple 148V DC Voltage source the speed
of DC Motor is 1150 RPM,armature current is 1.81 A,field current is
0.9867A and electrical torque obtained is 2.204 N-m.
➢When DC Motor is fed by chopper (buck-boost converter) and input of
chopper is a 100V DC supply and duty cycle of chopper is 70% and hence
the output voltage of chopper obtained is as 148V.
➢For the same voltage of chopper’s output voltage of 148V, the speed of DC
Motor is 2603 RPM, armature current is 4.66A, field current is 0.5236A and
electrical torque is obtained as 2.318 Nm.
➢Output voltage waveform of chopper has ripples which will reduce the
performance of DC motor.

14. CONCLUSION-
➢The performance of a dc motor is analysed for two cases, first is to give a constant
dc supply, and that of second scheme is used to vary the armature voltage of DC
Motor by chopper.
➢Comparison of speed,armature current,field current and electrical torque is explained
graphically.
➢In case of chopper fed dc motor, it behaves as a speed control of a dc shunt motor.
➢The performance of DC Motor is different in case of chopper fed supply as speed is
high,armature current is high and also torque is high.
➢This happens due to use of power electronics converters and it’s output has ripple.
➢In our case we can see that chopper output wave form has ripple and it is not purely
DC as in first case.
➢It can be concluded that although power electronics converters is very useful in
controlling the electrical machines but it distort the output as well as input supply
also and also harmonics is introduced in ac supply.

15. REFERENCES-
[1] Bimbhra, P.S., Power Electronics, 3rd edition, Khanna Publishers, 2004.
[2]D.P Kothari and I .J. Nagrath , “ Electric Machine ”, Tata Mc Grew Hill Education.
[3] Mohan, Ned, Power Electronics, 2nd edition, John Wiley & Sons, New York, 1995.
[4] Bimbhra, P.S, “Generalized theory of electric machine” ,Khanna Publisher.
[5] Mohammed Aslam Husain, Mohammad Ahmad and Adil Sarwar, “Simulation and Analysis
of a Multilevel Converter (MLC) for grid applications”, National Conference on “Power
Energy Instrumentation and control PIECON 11”, Aligarh Muslim University, Feb 2011.
[6] Abu Tariq, Mohammed Aslam Husain, Mohammad Ahmad and Mohd. Tariq, “Simulation
and Study of a grid connected Multilevel Converter (MLC) with varying DC input”, IEEE
Conference on “Environment and Electrical Energy International Conference EEEIC 2011”,
Italy, Rome May 2011.
[7] G. Mahesh, Manivanna Kumar and S. Rama Reddy, “Simulation and Experimental Results
of 7-Level Inverter System”, Research Journal of Applied Sciences, Engineering and
Technology,pp. 88-95, 2011.
[8] http://www.mathworks.com