Documentation

Speed Controller (AC)

Implement speed controller model for vector controlled AC motor drives

Library

Electric Drives/Fundamental Drive Blocks

Description

The Speed Controller (AC) block represents a PI speed regulator model for AC machines used in vector-controlled drives. It has two operating instances: the first with both torque and flux references outputs and the second with torque reference output only. The models of the first and second instances are shown in the figures.

Parameters

Controller Tab

Controller type

Specify the type of controller to use:

  • With flux reference output (default)

  • Without flux reference output

Regulation type

Specify the type of regulation to use:

  • Speed regulation (default)

  • Tourqe regulation

Base​ ​sample time (s)

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

Speed reference ramp (rpm/s) [Deceleration, Acceleration]

The maximum rate of change of the speed reference, in rpm/s, to keep the machine's currents within rated values. This parameter is required and enabled only if the Regulation type parameter is set to Speed regulation. The default value is [-1800,1800].

Proportional gain

The PI controller's proportional gain. This parameter is required and available only if the Regulation type parameter is set toSpeed regulation. The default value is 5.

Integral gain

The PI controller's integral gain. This parameter is required and available only if the Regulation type parameter is set to Speed regulation. The default value is 10.

Low-pass filter cutoff frequency (Hz)

The speed measurement first-order filter cutoff frequency, in hertz. This parameter is required and available only if the Regulation type parameter is set to Speed regulation. The default value is 100.

Output torque saturation (N.m) [Negative, Positive]

The minimum (negative) and maximum (positive) torque reference output limits, in newton-meter. The default value is [-17.8,17.8].

Sample time (s)

The speed-controller sampling time, in seconds. The sampling time must be a multiple of the simulation time step. The default value is 100e-6.

Machine Tab

Nominal frequency (Hz)

The nominal frequency of the machine, in hertz. This parameter is required and available only if the Speed controller type parameter is set to With flux reference output. The default value is 60.

Pairs of poles

The number of pole pairs. This parameter is required and available only if the Speed controller type parameter is set to With flux reference output. The default value is 2.

Nominal flux (Wb)

The nominal flux for the machine, in weber. This parameter is required and available only if the Speed controller type parameter is set to With flux reference output. The default value is 0.3.

Inputs and Outputs

N

The speed of the machine, in rpm.

N*

The speed reference of the machine, in rpm. When the Regulation type parameter is set to Torque regulation, this input refers to the torque reference of the machine.

MagC

A binary signal indicating if the machine is magnetized enough to be started (1) or not (0). This signal is typically provided by another controller that has the capacity to establish the magnetization level of the machine, for example, the Field-Oriented Controller.

This input is available only if the Speed controller type parameter is set to With flux reference output.

Torque*

The torque reference, in newton-meter.

Ctrl

A bus containing these measurements:

  • Torque reference — In newton-meter.

  • Flux reference (Wb) — This signal is available only when the Speed controller type parameter is set to With flux reference output.

  • Error — When the Regulation type parameter is set to Speed regulation, this signal is the speed error (difference between the reference and actual speed). Otherwise, it is zero.

  • Reference — The speed reference, in rpm. When the Regulation type parameter is set to Torque regulation, this measurement refers to the torque reference, in newton-meter.

Flux*

The flux reference, in weber. This output is available only when the Speed controller type parameter is set to With flux reference output.

Examples

The Speed Controller (AC) block is used in the AC3, AC4, AC5, AC6, and AC7 blocks from 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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