Example: DCMOTOR
DC Motor-open loop

Purpose

To understand the dynamics of the response of a d.c. motor.

The motor is a permanent magnet machine, assumed to have a constant field flux and to have a linear model with the parameters listed. It is a third order model having two time constants, the electrical one L/R and the mechanical one J/B, and an integrator to go from speed to position.

System excitation

The input is taken to be a constant voltage V applied at t = 0.

Task

Calculate for the default parameters the steady state speed attained by the motor. Check this from the simulation. Note also that when the speed becomes constant the position increases lineary with time, i.e. integration of v gives vt.

System Parameters

J	3.2284E-6	`J` = 3.2284.10^–6	[kg.m²]	moment of inertia of the rotor
B	3.5077E-6	`B` = 3.5077.10^–6	[N.m.s/rad]	damping ratio of the mechanical system
K	0.0274	`K` = 0.0274	[Nm/Amp]	electromotive force constant
R	4	`R` = 4	[Ω]	electric resistance
L	2.75E-6	`L` = 2.75.10^–6	[H]	electric inductance

Last Update

May 20, 2012