Project - Speed Control of a Direct Current (DC) motor

* A proportional, integral and derivative (PID) controller can be designed to maintain the desired load voltage using appropriate field excitation.

*Using kirchoff's voltage law,one can drive

Vs=Ra ia+La dia/dt +Vb

*Back EMF, angular velocity,and torque are related by

Vb=Km d.0'/dt. t=kt.i

*Here,Km and It are the back EMF and torque constants respectively

*Angular velocity w=0'

*The open loop-transfer function for the motor with the speed (w) and supply voltage (Vs) can be derived as

W(s)/Vs(s)= Kt/(J La S^2+(JRa+BLa)s+(BRa+Kt Km)

*A proportional, integral and derivative (PID) controller design is demonstrated to obtain the desired angular speed using the appropriate supply voltage.

PID controller to regulate the speed control of the DC motor:

Frist set all the parameters are given below

% DC_Motor_design parameters

J=0.01%moment of inertia of the rotor(kgm^2)

B=0.1%motor viscous friction constant (Nms)

Km=0.01%Back EMF constant (v/radians/s)

Kt=0.01%motor torque constant (Nm/Ampere)

Ra=1%Armature resistance (ohm)

La=0.5%Armature inductance(Henry)

*Control design objectives

1.setting time<2s

2.overshoot<5%

3.steady State error<1%

*State space model

d/dt[0' ;i] = [-B/J Kt/J; -Km/La -Ra/La][o';i]+[0;1/La] Vs

y=[1 0];[0' ; i];

After completion of parameters now run it.then use a who comment then see all the variable's, then start the simulink

Open a simulink model to create one simulink file like (DC_motor_design)

Then open the simulink library

• Darg all the required block are namely below steps

1. Step block

2.gain block

3.Sum block

4.transfer function block

5.clock source

6.work space block

7.scope

• Then change all the blocks parameters what we required
• The above blocks are connect with required format
• Then name it and connect the blocks
• Now set the modelling settings with required format (ode4 -Rungakutta method) i pick.
• Then save it and run the simulink model ( Attached below)
• Finally scope the blocks,now i got scope results are attached below

Finally getting all the required PID controller DC motor design data's.....