A simplified mathematical model of Brushed DC motor can be easily find in the many control theory books. The mathematical model is composed by the electrical constant: inductance, resistance and EMF, and the mechanical constants: inertial, viscous damping. This system can be model by a third order differential equation. In the cases, where the electrical dynamics can be neglected (due to be much faster than the mechanical) this system become a second order model.
My question is about the brushless DC motor. The brushless DC has 3: inductance, resistance and EMF (1 per phase), the mathematical description of this type of motor is more complicated than the brushed DC.
Then, are there a simplified model of Brushless DC that is equivalent of Brushed DC motor? Can the brushless DC motor be simplified to the same equivalent system of a brushed dc motor (parameters: torque constant, resistance and indutancte)?
The purpose of this model is only to get an rough idea of dynamic behavior of the system.
Thanks.
Hi!
See some info there:
http://www.mathworks.com/help/physmod/sps/powersys/ref/permanentmagnetsynchronousmachine.html
I think that you should make the simplified model of electromagnetical subsystem and add standart mechanical subsystem to it. You must take into account that in Brushed DC motor there are two inputs (voltage and load torque) and in BLDC motor there three inputs (voltage, frequency and load torque).
Main difference PMSM with trapezoidal EMF (BLDC motor) from PMSM with sinusoid EMF (PMSMS) is that: in PMSMS rotor speed depend on voltage frequency while in BLDC motor voltage frequency depend on rotor speed.
I know that at UNH from the early 70's to the 90's C.K. Taft did a lot of work on modelling these motor types. You might check his papers.
- Badges
- Science topic
- Similar topics
- Engineering
- Control Theory