SPRUHJ1I January 2013 – October 2021 TMS320F2802-Q1 , TMS320F28026-Q1 , TMS320F28026F , TMS320F28027-Q1 , TMS320F28027F , TMS320F28027F-Q1 , TMS320F28052-Q1 , TMS320F28052F , TMS320F28052F-Q1 , TMS320F28052M , TMS320F28052M-Q1 , TMS320F28054-Q1 , TMS320F28054F , TMS320F28054F-Q1 , TMS320F28054M , TMS320F28054M-Q1 , TMS320F2806-Q1 , TMS320F28062-Q1 , TMS320F28062F , TMS320F28062F-Q1 , TMS320F28068F , TMS320F28068M , TMS320F28069-Q1 , TMS320F28069F , TMS320F28069F-Q1 , TMS320F28069M , TMS320F28069M-Q1
If the motor inertia has been previously estiamted, or the motor inertia is known, you can accelerate the system start-up time by bypassing the inertia estimation process. The inertia estimation process should be done during development with a representative inertia attached to the motor shaft. Since the motor inertia is configured during development, SpinTAC Velocity Identify does not need to be included in the final product.
The motor inertia is required for the SpinTAC speed controller. In MotorWare labs, motor inertia is configured as a default value in ST_MOTOR_INERTIA_A_PER_KRPM, located in spintac.h. This definition is covered in greater detail in Section 5.7.1.1. More information on SpinTAC Velocity Identify can be found in Section 8.
If your project does not use MotorWare, the motor inertia is set in the SpinTAC speed controller during the initialization process using the Inertia parameter in the SpinTAC speed controller global structure. The unit for Inertia is PU/(pu/s2). Where PU is the user unit for current [A] and pu/s2 is the user unit for acceleration [krpm/s]. Typically inertia is specified in Kg*m2 or N*m*s2. The user must convert the real world inertia unit into the scaled unit that is used by the SpinTAC speed controller.
Equation 26 can be used to convert between inertia specified in Kg*m2 and the scaled units that are needed for the SpinTAC speed controller. The result of this equation should be provided as the Inertia input to the SpinTAC speed controller.
In this equation, the following symbols are used:
While you can use this equation to calculate the inertia of your system, it is always preferred to use SpinTAC Velocity Identify to estimate the system inertia. This will provide the most accurate value of the system inertia and will take into account objects that might be difficult to calculate the inertia of.