AFT

Category: Toolbox > eDrives > 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.

•      RSonLine: Binary control over online estimation of stator resistance.

•      RS ID: Binary input control over estimation of resistance at startup, which is 100Hz block.

•      RSEnable: Binary control over enabling stator resistance estimation.

•      RS Recal: Binary control over recalibration of stator resistance.

Outputs:

•      Cos: Cosine of the estimated angular position.

•      Sin: Sine of the estimated angular position.             

•      Flux: Estimated flux value from flux tracker.

•      Speed: Estimated rotor shaft speed.

•      Rs: d-axis current injection for estimating online stator resistance.

•      RsRecal: d-axis current injection for estimating stator resistance at startup.

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, flux, and online stator resistance of a motor while it is spinning in real time. Optionally, the AFT block can estimate rotor resistance for induction motors.

Graphical user interface Description automatically generated

 

AFT Parameters

AFT Gain: Specifies the gain value to efficiently estimate shaft speeds at low speeds for different machines. It is chosen when operating under sensorless conditions around the zero-speed range.

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

R 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.

Full Scale Values

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

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

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

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

Motor Parameters

D-axis Inductance-Ld (H): Indicates the measured d-axis stator inductance of the motor.

Enable Rotor Resistance Estimation(for Induction Motors): Lets you access rotor resistance estimation.

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

PM Flux (Wb): Indicates the estimated or calculated permanent magnetic flux.

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

Stator Resistance Rs (ohms): Indicates the measured stator resistance of the motor.

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