Populating the Simulink BLDC block for behavioral simulation of the motor

Hello MathWorks community,

I am building a control system simulation model for a BLDC motor used in an electric vehicle.

However, I cannot find some data to enter in the fields:

• Maximum permanent magnet flux linkage
• Rotor angle range over which the permanent magnet flux linking the stator winding is constant

possibly use:

• Maximum rotor-induced back EMF

In addition, I should also characterize the motor from a thermal aspect, so that I can make assessments on the type of cooling to be used and the working conditions under which it might operate: how could I “theoretically” derive the values to be entered in the fields:

1) Temperature Dependence

2) Thermal Port

Thank you in advance.

[Umar]

Hi @Leonardo,

Perhaps clicking the link below will help answer your questions.

Electric Vehicle Powered by BLDC Motor

[Leonardo]

Thank you very much!

I am working on something very similar!

Thank you!

Answer 1

[Sabin]

Below some tips for BLDC parameterization:

'Rotor angle range over which back emf is constant' can be set to pi/(2*NumberOfPolePairs) rad

'Maximum permanent magnet flux linkage' or 'Maximum rotor-induced back EMF' should be know from motor specification (either datasheet or tests)

Parameters under Temperature Dependence:

• Resistance temperature coefficient: for copper is 0.00393 1/K
• Permanent magnet flux coeffcient: can be approximated with -0.001 1/K for neodymium magnets
• Measurement temperature: for the above data we can use 298.15 K (that is 25 Celsius degrees)

Thermal Port:

• These parameters will be characteristic to the motor. Thermal mass is the product between winding/rotor mass in kg and specific heat capacity in J/(kg*K). The specific heat capacity for copper is approximately 385 J/(kg·K).

[Leonardo]

Thank you, this is data that I had basically already considered and this confirms that I was on the right track!

Thank you very much for the response!