# Simplified Synchronous Machine

**Libraries:**

Simscape /
Electrical /
Electromechanical /
Synchronous

## Description

The Simplified Synchronous Machine block models a simplified synchronous machine with a voltage source that represents electromotive force (EMF). You can specify the internal resistance and inductance with per-unit or SI parameters.

The equivalent circuits of the simplified synchronous machine for the direct axis, the quadrature axis, and the zero sequence are:

### Equations

The simplified synchronous machine equations are expressed with respect to a rotating reference frame, which is defined by:

$${\theta}_{e}(t)=N{\theta}_{r}(t),$$

where:

*θ*is the electrical angle._{e}*N*is the number of pole pairs.*θ*is the rotor angle._{r}

The Park transformation maps the synchronous machine equations to the rotating reference frame with respect to the electrical angle. The Park transformation is defined by:

$${P}_{s}=\frac{2}{3}\left[\begin{array}{ccc}-\mathrm{cos}{\theta}_{e}& -\mathrm{cos}({\theta}_{e}-\frac{2\pi}{3})& -\mathrm{cos}({\theta}_{e}+\frac{2\pi}{3})\\ \mathrm{sin}{\theta}_{e}& \mathrm{sin}({\theta}_{e}-\frac{2\pi}{3})& \mathrm{sin}({\theta}_{e}+\frac{2\pi}{3})\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right].$$

The Park transformation is used to define the per-unit simplified synchronous machine equations. The voltage equations are defined by:

$${e}_{d}=\frac{1}{{\omega}_{base}}\frac{\text{d}{\psi}_{d}}{\text{d}t}-{\Psi}_{q}{\omega}_{r}+R{i}_{d}+{v}_{d}$$

${e}_{q}=\frac{1}{{\omega}_{base}}\frac{\text{d}{\psi}_{q}}{\text{d}t}+{\Psi}_{d}{\omega}_{r}+R{i}_{q}+{v}_{q}$

$${e}_{0}=\frac{1}{{\omega}_{base}}\frac{d{\Psi}_{0}}{dt}+R{i}_{0}+{v}_{0}$$

where:

*e*,_{d}*e*, and_{q}*e*are the_{0}*d*-axis,*q*-axis, and zero-sequence voltages, defined by:$$\left[\begin{array}{c}{e}_{d}\\ {e}_{q}\\ {e}_{0}\end{array}\right]={P}_{s}\left[\begin{array}{c}{e}_{a}\\ {e}_{b}\\ {e}_{c}\end{array}\right].$$

*e*,_{a}*e*, and_{b}*e*are the per-unit internal voltage sources, defined by:_{c}$$\begin{array}{l}{e}_{a}={E}_{pu}sin{\theta}_{e}\\ {e}_{b}={E}_{pu}sin({\theta}_{e}-120\text{\xb0)}\\ {\text{e}}_{c}={E}_{pu}sin({\theta}_{e}+120\text{\xb0)}\end{array}$$

*e*is the per-unit amplitude of the internal generated voltage._{pu}*v*,_{d}*v*, and_{q}*v*are defined by:_{0}$$\left[\begin{array}{c}{v}_{d}\\ {v}_{q}\\ {v}_{0}\end{array}\right]={P}_{s}\left[\begin{array}{c}{v}_{a}\\ {v}_{b}\\ {v}_{c}\end{array}\right].$$

*v*,_{a}*v*, and_{b}*v*are the stator voltages measured from port_{c}**~**to neutral port**n**.*ω*is the per-unit base electrical speed._{base}*ψ*,_{d}*ψ*, and_{q}*ψ*are the_{0}*d*-axis,*q*-axis, and zero-sequence flux linkages.*ω*is the per-unit rotor rotational speed._{r}*R*is the stator resistance.*i*,_{d}*i*, and_{q}*i*are the_{0}*d*-axis,*q*-axis, and zero-sequence stator currents, defined by:$$\left[\begin{array}{c}{i}_{d}\\ {i}_{q}\\ {i}_{0}\end{array}\right]={P}_{s}\left[\begin{array}{c}{i}_{a}\\ {i}_{b}\\ {i}_{c}\end{array}\right].$$

*i*,_{a}*i*, and_{b}*i*are the stator currents flowing out of port_{c}**~**.

The stator flux linkage equations are defined by

$$\begin{array}{l}{\psi}_{d}=L\cdot {i}_{d}\\ {\psi}_{q}=L\cdot {i}_{q}\\ {\psi}_{0}=L\cdot {i}_{0}\end{array}$$

where *L* is the stator leakage inductance.

The power equation of the simplified synchronous machine in per-unit is defined by:

$$P={e}_{d}{i}_{d}+{e}_{q}{i}_{q}.$$

### Plotting and Display Options

You can perform plotting and display actions using the
**Electrical** menu on the block context menu.

Right-click the block and, from the **Electrical** menu, select one of these options:

**Display Base Values**— Displays the machine per-unit base values in the MATLAB^{®}Command Window.**Display Associated Initial Conditions**— Displays associated initial conditions in the MATLAB Command Window.

### Model Thermal Effects

You can expose thermal ports to model the effects of generated heat and machine temperature. To expose the thermal ports, set the **Modeling option** parameter to either:

`No thermal port`

— The block does not contain thermal ports.`Show thermal port`

— The block contains multiple thermal conserving ports.

For more information about using thermal ports in actuator blocks, see Simulating Thermal Effects in Rotational and Translational Actuators.

### Variables

To set the priority and initial target values for the block variables prior to simulation,
use the **Initial Targets** section in the block dialog box or Property
Inspector. For more information, see Set Priority and Initial Target for Block Variables.

For this block, the **Initial Targets** settings are visible only if, in
the **Initial Conditions** section, you set the **Initialization
option** parameter to ```
Set targets for rotor angle and Park's
transform variables
```

.

Nominal values provide a way to specify the expected magnitude of a variable in a model.
Using system scaling based on nominal values increases the simulation robustness. Nominal
values can come from different sources, one of which is the **Nominal
Values** section in the block dialog box or Property Inspector. For more
information, see System Scaling by Nominal Values.

## Ports

### Input

### Output

### Conserving

## Parameters

## Extended Capabilities

## Version History

**Introduced in R2020b**