Induction Machine Scalar Control

Induction machine V/f control

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Libraries:
Simscape / Electrical / Control / Induction Machine Control

Description

The Induction Machine Scalar Control block implements an induction machine scalar, that is V/f or V/Hz, control structure. The diagram shows the open-loop V/f control structure that the block implements.

Equations

The Induction Machine Scalar Control block computes the magnitude of the stator voltage based on the reference frequency, $f_s^{*}$, as:

$V_s^{*}=\left(\frac{V_n-V_{min}}{f_n-f_{min}}\right)f_s^{*},$

where:

• V_n is the rated voltage.

• V_min is the minimum voltage.

• f_n is the rated electrical frequency.

• f_min is the minimum frequency.

The voltage components in the stationary reference frame are:

$V_{\alpha }=V_s^{*}\text{cos}(2\pi f_s^{*}t)$

and

$V_{\beta }=V_s^{*}\text{sin}(2\pi f_s^{*}t).$

The block obtains V_abc from V_α and V_β by using an inverse Clarke transformation.

Examples

Asynchronous Machine Scalar Control

Control the rotor speed in an asynchronous machine (ASM) drive using the scalar V/f control method. The converter transforms a reference speed to a reference electrical frequency. The controller generates reference voltages from the reference frequency by maintaining a constant voltage-to-frequency ratio through scalar V/f control.

• Open Model

Ports

Input

fRef — Frequency

scalar

Reference electrical frequency.

Example: Example

Data Types: single | double

Output

Vabc — Voltage

vector

Reference phase voltages.

Example: Example

Data Types: single | double

Parameters

Rated electrical frequency (Hz) — Frequency

60 (default) | positive scalar

Nominal frequency.

Rated voltage (V) — Voltage

550 (default) | positive and greater than the value of the Minimum voltage (V) parameter

Nominal voltage.

Minimum voltage (V) — Voltage

10 (default) | zero or positive

Lower bound for the voltage.

Sample time (-1 for inherited) — Block sample time

-1 (default) | positive scalar

Time, in s, between consecutive block executions. During execution, the block produces outputs and, if appropriate, updates its internal state. For more information, see What Is Sample Time? and Specify Sample Time.

If this 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 using a positive scalar.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2017b