Separate or Parallel Excitation DC Machine

A1 and A2 are the rotor (armature) winding terminals. F1 and F2 are the stator (field) winding terminals. Both the stator and rotor winding use the single phase variant of the current source interface.

Electrical sub-system model

The electrical part of the machine is represented by the following system of equations. All electrical variables and parameters of the armature circuit are marked with the subscript a, and variables and parameters of the field winding circuit are denoted with the subscript f.

. $\left[\begin{array}{c}\begin{array}{c}{v}_a\\ v_f\end{array}\end{array}\right]=\left[\begin{array}{cc}{R}_a& 0\\ 0& R_f\end{array}\right]\left[\begin{array}{c}\begin{array}{c}{i}_a\\ i_f\end{array}\end{array}\right]+\frac{d}{dt}\left[\begin{array}{c}\begin{array}{c}{\psi }_a\\ {\psi }_f\end{array}\end{array}\right]+\left[\begin{array}{c}\begin{array}{c}\begin{array}{c}{\omega }_r\psi \end{array}\\ \begin{array}{c}0\end{array}\end{array}\end{array}\right]$

$\psi =L_{af}{i}_f$

$T_e=\psi i_a$

Mechanical sub-system model

Motion equation:

Ports

• A1 (electrical)
  • Rotor (armature) winding port 1.

• A2 (electrical)
  • Rotor (armature) winding port 2.

• F1 (electrical)
  • Stator (field) winding port 1.

• F2 (electrical)
  • Stator (field) winding port 2.

• in
  • Available if Model Load source is selected

Electrical (Tab)

Mechanical (Tab)

• Jm
  • Combined rotor and load moment of inertia [kgm2]
• Friction coefficient
  • Machine viscous friction coefficient [Nms]
• Unconstrained mechanical angle
  • Limiting mechanical angle between 0 and 2π

Load (Tab)

External load enables you to use an analog input signal from a HIL/TyphoonSim (internal virtual IO bus in TyphoonSim) analog channel with the load_ai_pin address as an external torque/speed load, and to assign offset (V) and gain (Nm/V) to the input signal, according to the formula:

$T_l=load\_ai\_gain·\left(AI\right(load\_ai\_pin)+load\_ai\_offset)$

Feedback (Tab)

If an external resolver carrier source is selected, the source signal type can be set as either single ended or differential. The single ended external resolver carrier source type enables use of an analog input signal from the HIL/TyphoonSim (internal virtual IO bus in TyphoonSim) analog channel with the res_ai_pin_1 address as the external carrier source. Additionally, offset (V) and gain (V/V) values can be assigned to the input signal, according to the formula:

The differential external resolver carrier source type enables use of two analog input signals from the HIL/TyphoonSim (internal virtual IO bus in TyphoonSim) analog channels with the res_ai_pin_1 and the res_ai_pin_2 addresses. Analog signals from these HIL/TyphoonSim (internal virtual IO bus in TyphoonSim) analog inputs are subtracted, and the resulting signal is used as the external differential carrier source. Additionally, offset (V) and gain (V/V) values can be assigned to the input signal (similarly to the single ended case), according to the formula:

The following expression must hold in order to properly generate the encoder signals:

Table 3. Variables in the encoder limitation expression

symbol	description
enc_ppr	Encoder number of pulses per revolution
fm	Rotor mechanical frequency [Hz]
Ts	Simulation time step [s]

Snubber (Tab)

• Rsnb rotor
  • Rotor snubber resistance value [Ω]

• Rsnb stator
  • Stator snubber resistance value [Ω]

All machines with current source based circuit interfaces have the Snubber tab in the properties window where the value of snubber resistance can be set. Snubbers are necessary in the cases when an inverter or a contactor is directly connected to the machine terminals. This value can be set to infinite (inf), but it is not recommended when a machine is directly connected to the inverter since there will be a current source directly connected to an open switch. In this case, one of each switch pairs S1 and S2, S3 and S4, and S5 and S6 will be forced closed by the circuit solver in order to avoid the topological conflicts. On the other hand, with finite snubber values, there's always a path for the currents Ia and Ib, so all inverter switches can be open in this case. Circuit representations of this circuit without and with snubber resistors are shown in Figure 5 and Figure 6 respectively. Snubbers are connected across the current sources.

Note: Snubbers exist only in the machine components that have the current source based circuit interface.

Note: Snubbers are dynamic, which means that the snubber is dynamically added to circuit modes where topological conflicts are detected.

Output (Tab)

• Execution rate
  • Signal processing output execution rate [s]
• Electrical torque
  • Machine electrical torque [Nm]
• Mechanical speed
  • Machine mechanical angular speed [rad/s]
• Mechanical angle
  • Machine mechanical angle [rad]
• Field winding flux
  • Field flux [Wb]
• Armature winding emf
  • Armature induced back emf [V]

Extras (Tab)

The Extras tab gives you the opportunity to set Signal Access Management for the component.