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

Aim: To design a Simulink model for the DC motor shown in Figure 1. and also by Using the Proportional, Integral, and Derivative (PID) control design knowledge gained in the training to design, develop and test a controller to maintain a desired speed for the motor.

Answer:

• Here the Speed control of a DC motor is either done manually by the operator or by means of an automatic control device.
• This is different from speed regulation where the speed is trying to be maintained or regulated against the natural change in speed due to a change in the load on the shaft

• so the speed can be varied by changing the:

  1. The terminal voltage of the armature V
  2. The external resistance in the armature circuit R_a
  3. The flux per pole

• So Terminal voltage and external resistance involve a change that affects the armature circuit while flux involves a change in the magnetic field

• so Therefore speed control of a DC motor can be classified into the:

  1. Armature Control Methods
  2. Field Control Methods

Simulink model :

• Here first we need to create a Simulink model of the DC motor and make it a subsystem called the DC motor
• So next the subsystem of the DC motor is connected to the discrete PID controller which helps in maintaining the desired speed
• So after the PID controller, we need to start with the kp ki kd such as 1.0 1.0 0 after tuning accordingly so by this we can adjust the kp ki kd values as 31.5 82.3 2.3
• Which is used to obtain the control design objectives

Matlab script:

Here we consider the following parameters:

% This file contains the design parameters to model a Dc motor
J = 0.01; % moment of inertia
B = 0.1; % motor friction
Km = 0.01; % back emf
Kt = 0.01; % Motor torque constant
Ra = 1.0; % aramture resistance
La = 0.5; % armature inductance

Here we consider the following parameters:

Here we consider the PID control parameters as :

Kp =1 ki = 1 kd 0

But after tuning we set kp ki kd to 31.5 82.3 2.3 which is used to obtain the control objectives of the settling time overshoot time and steady-state error

Now For maintaining the stability of a dynamic system :

Output results:

Case: 1 When maintaining the desired speed of the motor at 100 :

Case: 2 When maintaining the desired speed of the motor at 230v :

• Here by observing the above two graphs, we change the desired speed to 100 in the case1 and 230 in case 2
• But here both the plots remain same
• So by this, we can say that we maintained the desired speed of a DC motor

Conclusion:

we have designed In this project a Simulink model for the DC motor as shown in Figure 1. and also we Use the Proportional Integral and Derivative PID control design knowledge gained in the training to design develop and test a controller to maintain a desired speed for the motor.

Note: While attaching the model system got stuck so attached all the results.