Documentation

Vector Controller (WFSM)

Implement vector controller model for a wound-field synchronous machine (WFSM)

Library

Electric Drives/Fundamental Drive Blocks

Description

The WFSM vector controller offers fast transient response and DC-machine-like performance to a WFSM drive as the stator flux and developed torque are independently controlled.

The WFSM vector controller model has two operating modes, detailed and average, for a detailed or average-value inverter, respectively.

Detailed mode

In detailed mode, the Vector Controller (WFSM) block contains five main blocks.

  • The Flux estimator block estimates the motor stator flux Ψdqss.

  • The Flux PI controller regulates the flux in the machine.

  • The dq-abc block performs the conversion of the dq current components into abc-phase variables.

  • The current regulator is a bang-bang current controller with adjustable hysteresis bandwidth.

  • The magnetization control unit contains the logic used to switch between the magnetization and normal operation mode.

Average mode

In average mode, the high-frequency switching actions of the power switches are not represented.

Average mode is similar to detailed mode except that the pulses generated by the current regulator are three-level signals (-1, 0, 1). These signals indicate whether the average-value inverter applies a negative, zero, or positive DC bus voltage (Vdc) to the machine during inverter saturation. In detailed mode, the Vector Controller (WFSM) block outputs the actual pulses for the inverter switches.

Parameters

Model detail level

Specify the model detail level to use:

  • Detailed (default)

  • Average

Base​ ​sample time (s)

The time step used for the simulation, in seconds. The default value is ​2​e-6.

Proportional gain

The flux controller proportional gain. The default value is 1000.

Integral gain

The flux controller integral gain. The default value is 1000.

Low-pass filter cutoff frequency (Hz)

The flux estimation first-order filter cutoff frequency, in hertz. The default value is 2.

Output voltage saturation (V) [Negative, Positive]

The minimum and maximum voltage applied to the motor excitation field, in volts. The default value is [-300,300].

High voltage field magnetization time (s)

The field magnetization high- voltage application time, in seconds. The default value is 0.2.

Field magnetization voltage (V)

The field magnetization voltage applied to establish the stator flux, in volts. The default value is 600.

Total field magnetization time (s)

The total time before the drive is ready to produce a torque, in seconds. The default value is 1.

Field nominal voltage (V)

The field nominal voltage, in volts. The default value is 30.

Current hysteresis bandwidth (A)

The current regulator hysteresis bandwidth, in amperes. This value is the total hysteresis bandwidth distributed symmetrically around the current set point. The figure shows a case where the current set point is Is* and the current regulator hysteresis bandwidth is set to dx.

The default value is 10.

Sample time (s)

The vector-controller sampling time, in seconds. The sampling time must be a multiple of the simulation time step. The default value is 20e-6.

Stator resistance (Ohms)

The stator phase resistance Rs, in ohms, of the motor. The default value is 2.01e-3.

Motor pairs of poles

The number of pole pairs. The default value is 2.

Inputs and Outputs

iabc

The three line currents of the WFSM.

Vabc

The three-phase voltage of the WFSM.

Te*

The torque reference, typically provided by a speed controller.

Flux*

The flux reference, typically provided by a speed controller.

Pulses

The pulses for the six inverter switches. This output is visible only when the Model detail level parameter is set to Detailed.

Vf

Field voltage for the WFSM.

Mag_C

This binary signal indicates if the machine is magnetized (1) enough to be started or not (0).

Sig*

A vector containing measurement signals:

  • Iabc — The three line currents.

  • iabc* — The three reference currents.

  • pulses* — Two three-level signals (-1, 0, 1) indicating whether the average-value inverter applies a negative, zero, or positive DC bus voltage (Vdc) to the machine.

  • Mag_c — Binary signal that indicates if the machine is magnetized enough to be started (1) or not (0).

This output is visible only when the Model detail level parameter is set to Average.

Examples

The Vector Controller (WFSM) block is used in the AC5 block of the Electric Drives library.

References

[1] Bose, B. K. Modern Power Electronics and AC Drives, NJ: Prentice-Hall, 2002.

Introduced in R2015b

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