Project - Speed Control of a Direct Current (DC) motor
DESIGN CODE FOR DC MOTOR
% dc-motor design parameters
J=0.01; % moment of inertia of rotor
B=0.1; % viscous constant
Km=0.01; % back emf constant
Kt=0.01; % torque conatant
Ra=10; % armature resistance
La=0.1; % armature inductance
% basic mathematical modelling equations
% Ia=(Vs-Vb)/Za.....armature current
% Za=(LaS+Ra).......armature impedance
% T=Kt*Ia...........Torque equation
% Vb=Km*w...........back enf equation
DESIGN CODE FOR PID CONTROLLER
% PID controller design for dc motor speed control
fn=1.0;
wn=2*pi*fn;
z=0.5; %zeta for a under-damped system
p1=-z*wn+wn*sqrt(z^2-1);
p2=-z*wn-wn*sqrt(z^2-1);
P=[p1;p2]; % finding system poles
Kp=wn^2; % finding positional gain
Kd=2*z*wn; % finding derivative gain
%Kp and Kd can also foumd by place command using state space mateices A,B
Ki=8000; % initiating integral gain
CONCLUSION
By using PID controller for dc motor .....speeds can be controlled in smooth manner......and also by increasing Ki-value... with suitable Kp and Kd values .....the steady-state error,rise time ,peak over shoot can be minimised to a desired value.......Thank you sir/madam.