AFT

Category:  eDrives > Toolbox > Sensorless

Inputs:

•      Ialpha: Motor current in alpha-axis measured from ADC channels.

•      Ibeta: Motor current in beta-axis measured from ADC channels.

•      Valpha: Motor voltage in alpha-axis measured from ADC channels.

•      Vbeta: Motor voltage in beta-axis measured from ADC channels.

Outputs:

•      Cos: Cosine of the estimated angular position.

•      Sin: Sine of the estimated angular position.             

Description: The AFT block tracks the flux vector while the drive is running. It estimates the rotor angular position and shaft speed. It also tracks and provides torque and flux of a motor while it is spinning in real time. The AFT block estimates stator phase resistance, and optionally, it can estimate rotor resistance for induction motors.

 

Inverter Properties

Full Scale Current (A): Specifies the full-scale current value for normalization.

Full Scale Frequency (Hz): Specifies the full-scale frequency value for normalization.

Full Scale Voltage (V): Specifies the full-scale voltage value for normalization.

Voltage Filter (Hz): Specifies the corner frequency for low-pass voltage filters used for estimation and power calculation.

Motor Parameters

Flux (Wb): Specifies the estimated or calculated magnetic flux for one phase. It is important to provide the proper value of the magnetic flux for PM motors.

Rs Estimation Current (A): Specifies a DC injection current, which is introduced to the d-axis current for estimation of stator resistance.

Speed Filter (Hz): Specifies the corner frequency for the speed estimator inside the AFT.

Stator Inductance-Lq (H): Specifies the measured q-axis stator inductance of the motor.

Stator Resistance Rs (ohms): Specifies the measured stator resistance of one motor phase.

Rs Estimation scale: Specifies an empirical scale, which calibrates the estimator close to the stator resistance. Change this value to obtain an Rs max value close to the actual measured stator resistance.