Mechanical Model Configuration Page
In the the System Explorer window window configuration tree, expand the the Power Electronics Add-On custom custom device and select select Circuit Model >> 6-Ph PMSM BLDC >> Mechanical Model to display this page. Use this page to configure the PMSM BLDC Mechanical model.
This page includes the following components configurable at edit-time only:
Mechanical Model | ||||
Name | Specifies the name of the model. | |||
Description | Specifies a description for the model. | |||
Configuration | ||||
|---|---|---|---|---|
Symbol | Units | Default | Description | |
Viscous Damping | Fv | Newton*meter*second per radian | 0.00190986 Nm*s/rad | Combined viscous damping of the rotor and load, proportional to the angular velocity of the machine. |
Static Friction | Tf | Newton-meter | 0.3665 Nm | Static friction resisting initial rotation when the machine is at rest. |
Inertia | J | Kilogram-meter^2 | 0.0167309 Kg*m^2 | Moment of inertia of the rotor and load. |
Mechanical Model Section Channels
This section includes the following custom device channels. The value of an input channel can be modified dynamically at execution time.
Channel Name | Symbol | Type | Units | Default Value | Description | ||||
|---|---|---|---|---|---|---|---|---|---|
Mechanical Model Mode | Input | 0 (Speed Controlled) | Set this channel to one of the following values:
See the Mechanical Model Mode section for more information. | ||||||
User-Defined Speed | ωuser | Input | RPM | 0 RPM | Forces the speed of the machine to the defined value. This parameter is used in Speed Controlled mode, and ignored in Torque Controlled mode. | ||||
Load Torque | TL | Input | Nm | 0 Nm | Torque applied to the shaft of the machine. This parameter is used in Torque Controlled mode, and ignored in Speed Controlled mode. | ||||
Mechanical Angle | θm | Output | Degrees | 0° | Mechanical rotor position.
| ||||
Speed | ωm | Output | RPM | 0 RPM | Rotation speed of the machine rotor in RPM. | ||||
Total Torque | Ttotal | Output | Nm | 0 Nm |
|
Mechanical Model Description
Attached to the machine model's shaft is a basic mechanical model. This model was chosen due to its common application, and the ability to extend its functionality. The behavior of the model varies depending upon whether the Mechanical Model Mode is set to Torque Controlled (1) or Speed Controlled (0).
Torque Controlled
Because the 6-Phase PMSM BLDC model implements two electromagnetically independent 3-Phase PMSM BLDC models, we calculate the Speed (ωm) and Total Torque (Ttotal) by combining the two independent machines electromagnetic torques (Te1 and Te2). The result is a basic mechanical model which is mechanically coupled but not electrically coupled.
...
When the Mechanical Model Mode is set to Torque Controlled (1), the equation of the mechanical model can be expressed as follows:
| Mathblock | ||||
|---|---|---|---|---|
| ||||
\frac{\partial ω_m}{\partial t} = \frac{1}{J} * (T_{total} - F_v ω_m) |
where
| Mathblock | ||||
|---|---|---|---|---|
| ||||
T_{total}=(T_{e1}+T_{e2})-T_L-T_f |
...
There is a dead-zone implementation with the static friction torque; if the Electromagnetic Torque (Te) does not exceed the Static Friction (Tf) torque, the speed remains at zero.
Note that in equation
| Mathblock ref | ||
|---|---|---|
|
The following equation is used to calculate the machine power:
| Mathblock | ||||
|---|---|---|---|---|
| ||||
P_{m} = T_{total} * ω_m |
...
When the Mechanical Model Mode is set to Speed Controlled (0), the mechanical parameters (Viscous Damping, Static Friction, Inertia) are ignored. Instead, the rotor speed is directly set using the User-Defined Speed parameter, ωuser.
| Anchor | ||||
|---|---|---|---|---|
|
Select Speed Controlled mode if:
Your project requires you to manually set the speed of the machine
Your project has a mechanical model that requires you to input the speed of the machine in to the model
Select Torque Controlled mode if:
Your project requires you to manually set the load torque of the machine
Your project has a mechanical model that requires you to input the load toque of the machine in to the model