Loss models for DC machines

This package contains loss models used for DC machine models.

Extends from `Modelica.Icons.VariantsPackage`

(Icon for package containing variants).

Name | Description |
---|---|

`Brush` | Model considering voltage drop of carbon brushes |

`brushVoltageDrop` | Voltage drop of carbon brushes |

`Core` | Model of core losses |

`StrayLoad` | Model of stray load losses dependent on current and speed |

Model considering voltage drop of carbon brushes

Model of voltage drop and losses of carbon brushes. For currents between `-ILinear`

and `ILinear`

the voltage drop shows a linear behavior as depicted in Fig. 1.
For positive currents greater or equal than `ILinear`

the voltage drop equals `V`

.
For negative currents less or equal than `-ILinear`

the voltage drop equals `-V`

.

Fig. 1: Model of voltage drop of carbon brushes |

The voltage drop `v`

is the total voltage drop of all series connected brushes.

If it is desired to neglect brush losses, set `brushParameters.V = 0`

(this is the default).

Extends from `Modelica.Electrical.Analog.Interfaces.OnePort`

(Component with two electrical pins p and n and current i from p to n) and `Modelica.Thermal.HeatTransfer.Interfaces.PartialElementaryConditionalHeatPortWithoutT`

(Partial model to include a conditional HeatPort in order to dissipate losses, used for textual modeling, i.e., for elementary models).

Type | Name | Default | Description |
---|---|---|---|

`BrushParameters` | `brushParameters` | Brush loss parameters | |

`Boolean` | `useHeatPort` | `false` | =true, if heatPort is enabled |

Type | Name | Description |
---|---|---|

`PositivePin` | `p` | Positive electrical pin |

`NegativePin` | `n` | Negative electrical pin |

`HeatPort_a` | `heatPort` | Optional port to which dissipated losses are transported in form of heat |

Voltage drop of carbon brushes

Calculates the voltage drop of carbon brushes, according to Brush losses, e.g., used for initial equations.

Extends from `Modelica.Icons.Function`

(Icon for functions).

Type | Name | Description |
---|---|---|

`BrushParameters` | `brushParameters` | Brush loss parameters |

`Current` | `i` | Actual current |

Type | Name | Description |
---|---|---|

`Voltage` | `v` | Voltage drop |

Model of stray load losses dependent on current and speed

The stray load loss torque is

tau = PRef/wRef * (i/IRef)^2 * (w/wRef)^power_w

where `i`

is the current of the machine and `w`

is the actual angular velocity.
The dependency of the stray load torque on the angular velocity is modeled by the exponent `power_w`

.

The stray load losses are modeled such way that they do not cause a voltage drop in the electric circuit. Instead, the dissipated losses are considered through an equivalent braking torque at the shaft.

If it is desired to neglect stray load losses, set `strayLoadParameters.PRef = 0`

(this is the default).

Extends from `Modelica.Electrical.Analog.Interfaces.OnePort`

(Component with two electrical pins p and n and current i from p to n), `Modelica.Electrical.Machines.Interfaces.FlangeSupport`

(Shaft and support), and `Modelica.Thermal.HeatTransfer.Interfaces.PartialElementaryConditionalHeatPortWithoutT`

(Partial model to include a conditional HeatPort in order to dissipate losses, used for textual modeling, i.e., for elementary models).

Type | Name | Default | Description |
---|---|---|---|

`StrayLoadParameters` | `strayLoadParameters` | Stray load loss parameters | |

`Boolean` | `useHeatPort` | `false` | =true, if heatPort is enabled |

Type | Name | Description |
---|---|---|

`PositivePin` | `p` | Positive electrical pin |

`NegativePin` | `n` | Negative electrical pin |

`Flange_a` | `flange` | Shaft end |

`Flange_a` | `support` | Housing and support |

`HeatPort_a` | `heatPort` | Optional port to which dissipated losses are transported in form of heat |

Model of core losses

Core losses can be separated into *eddy current* and *hysteresis* losses. The total core losses
can thus be expressed as

p = PRef * (ratioHysteresis * (wRef / w) + 1 - ratioHysteresis) * (v / VRef)^2

where `w`

is the actual angular velocity and `v`

is the actual voltage. The term `ratioHysteresis`

is the ratio
of the hysteresis losses with respect to the total core losses for reference inner voltage and reference angular velocity.

For the voltage and angular velocity range with respect to Fig. 1,
the dependency of total core losses on the parameter `ratioHysteresis`

is depicted in Fig. 2.

Fig. 1: Voltage versus angular velocity |

Fig. 2: Core losses versus angular velocity with parameter `ratioHysteresis` |

In the current implementation it is assumed that `ratioHysteresis = 0`

. This parameter cannot be changed due to compatibility reasons.

Extends from `Modelica.Electrical.Analog.Interfaces.OnePort`

(Component with two electrical pins p and n and current i from p to n) and `Modelica.Thermal.HeatTransfer.Interfaces.PartialElementaryConditionalHeatPortWithoutT`

(Partial model to include a conditional HeatPort in order to dissipate losses, used for textual modeling, i.e., for elementary models).

Type | Name | Default | Description |
---|---|---|---|

`CoreParameters` | `coreParameters` | Armature core losses | |

`Boolean` | `useHeatPort` | `false` | =true, if heatPort is enabled |

Type | Name | Default | Description |
---|---|---|---|

`AngularVelocity` | `w` | Remagnetization angular velocity |

Type | Name | Description |
---|---|---|

`PositivePin` | `p` | Positive electrical pin |

`NegativePin` | `n` | Negative electrical pin |

`HeatPort_a` | `heatPort` | Optional port to which dissipated losses are transported in form of heat |