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ASM Flux Observer

Asynchronous machine flux observer

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  • Simscape / Power Systems / Simscape Components / Control / Observers

Description

The ASM Flux Observer block obtains the synchronous speed, ωe, and electrical angle, θe, that are required for performing rotor field-oriented control (FOC). The figure shows the equivalent circuit for the observer.

Equations

To determine the synchronous speed and electrical angle, the ASM Flux Observer block uses these relationships:

λdr'e=Lr'idr'e+LMidseLMimr,

0=Rr'idr'e(ωeωr)λqr'e+dλdr'edt,

and

iqr'e=LMLr'iqse,

in these combined forms:

idr'e=LMLr'(imridse)

dimrdt=Rr'Lr'(idseimr)

and

ωe=ωr+Rr'Lr'iqseimr

where:

  • λdr'e is the d-axis rotor flux.

  • imr is the magnetizing current.

  • idse and iqse are the d-axis and q-axis stator currents.

  • idr'e and iqr'e are the d-axis and q-axis rotor currents.

  • ωe is the synchronous speed.

  • ωr is the mechanical rotational speed.

  • Rr' is the rotor resistance, referred to the stator side.

  • Lr' is the rotor leakage inductance, referred to the stator side.

  • LM the magnetizing inductance.

Ports

Input

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Measured stator currents in the per-unit system.

Data Types: single | double

Measured rotational speed.

Data Types: single | double

Output

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Filtered d-axis and q-axis stator currents in the synchronous reference frame.

Data Types: single | double

Magnetizing rotor current.

Data Types: single | double

Rotor electrical angle.

Data Types: single | double

Rotor synchronous speed.

Data Types: single | double

Parameters

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Machine rated electrical frequency.

Rotor resistance, referred to the stator side, in the per-unit system.

Rotor leakage inductance, referred to the stator side, in the per-unit system.

Magnetizing inductance in the per-unit system.

Time constant used to low-pass filter the d-q currents.

Time interval between samples. If the block is inside a triggered subsystem, inherit the sample time by setting this parameter to -1. If this block is in a continuous variable-step model, specify the sample time explicitly. For more information, see What Is Sample Time? (Simulink) and Specify Sample Time (Simulink).

References

[1] Vas, P. Electrical Machines and Drives: A Space-vector Theory Approach. New York: Oxford University Press, 1992.

Introduced in R2017b

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