Diode

Description of the Diode component in Schematic Editor

Figure 1. Component Icon
Important: Before deciding to incorporate a Diode component in a real-time/VHIL model for highly demanding applications, it is recommended to first consider using an existing converter component. Doing so will ensure the highest model fidelity. If using a Diode component in a real-time/VHIL mode, it is recommended to use LC model switch.

Diode models

For real-time/VHIL simulation, there are two implementations available for the Diode: modeled as LC model switch, which is the preferred and also the default option, or as an ideal switch (Ron = 0, Roff = inf).

LC switch is modeled as a small inductance while conducting and a small capacitances while not-conducting. Weight of a Diode modeled as an LC switch switch is 0. The resistance parameter and the simulation step define the actual inductance and capacitance values according to the following equations:

L = T s ∙ R

C =   T s R

Where L and C are the calculated inductance and capacitance, Ts is the simulation step of electrical part of the model, R is the set resistance value.

If an ideal switch model is used, Diode is modeled as a short circuit when conducting and an open circuit when not conducting. In this case, a parallel snubber circuit can be defined. It can be a resistance or a series connection of a resistor and capacitor. Weight of a Diode modeled as an ideal switch is 1.

For simulation in TyphoonSim, Diode is modeled as changeable resistance (R_on/R_off).

Losses calculation

When the Losses calculation property is enabled, the Diode switching and conduction power losses will be calculated. Switching power losses are calculated as a function of current, voltage, and temperature using 3D Look-up tables (LUTs). Also, 2D input tables for losses is supported. When a 2D losses table is inserted, it assumes only current and temperature dependance. Conduction power losses can be defined as a function of current and temperature using Vd Look-up table. These LUTs can be either 1D or 2D. If the LUT is a 1D table, the forward voltage drop depends only on current. If the LUT is a 2D table, the forward voltage drop dependence on the junction temperature is included. Import options and an explanation how to correctly fill all necessary power losses parameters is described in the Importing power losses data section.

Note: An interactive overview of how you can incorporate power loss calculation in your model is available as part of the HIL for Power Electronics course on HIL Academy, as well as in the video Knowledgebase.

Available component properties are:

  • Current values - Switching elements current axis [A]
  • Voltage values - Switching elements switching losses, voltage axis [V]
  • Temp values - Switching elements temperature axis [°C]
  • Vd table - Diode forward voltage drop table, f(I,T) [V]
  • Ed off table - Diode switching OFF losses, output energy, f(I, V, T) [J]
Feature Not Supported: Losses calculation for this component is not supported in real-time/VHIL simulation yet.

Temperatures calculation

When the Temperatures calculation property is enabled, the diode combined power losses (P_loss) and junction temperatures (T_junctions) will be calculated. Combined power losses represent the sum of the calculated switching and conduction losses transferred through an internally generated Thermal network component. The internally generated Thermal network component also calculates junction temperatures from power losses, input cases temperatures, and provided thermal model parameters.

Note: An interactive overview of how you can incorporate temperature calculation in your model is available as part of the HIL for Power Electronics course on HIL Academy, as well as in the video Knowledgebase.

Additional temperatures calculation mask properties include:

  • Thermal networks type - Defines type of internal thermal network
  • Diode Rth - List of thermal resistances for Diode
  • Diode Tth / Diode Cth - List of thermal time constants or thermal capacitances for Diode
  • Calculations execution rate - Execution rate in [s] for the losses and temperatures calculation logic
Feature Not Supported: Temperature calculation for this component is not supported in real-time/VHIL simulation yet.

Ports

  • A (electrical)
    • Anode port of the Diode component.
  • K (electrical)
    • Cathode port of the Diode component.
  • T_junctions (in)
    • Available if Losses calculation is enabled and Temperature calculation is disabled
    • Used to provide junction temperature for diode losses calculations
    • T_junctions port is scalar - diode junction temperature
  • T_cases (in)
    • Available if Temperature calculation is enabled
    • Used to provide case temperature for the thermal model
    • T_cases port is scalar - diode case temperature
  • cond_losses (out)
    • Available if Losses calculation is enabled
    • Represents conduction losses of the diode
    • cond_losses port is scalar - diode conduction losses
  • sw_losses (out)
    • Available if Losses calculation is enabled
    • Represents switching losses of the diode
    • sw_losses port is scalar - diode switching losses
  • P_loss (out)
    • Available if both Losses and Temparature calculation are enabled
    • Represents sum of conduction and switching losses of the diode
    • P_loss port is scalar - sum of diode conduction and switching losses
  • T_junctions (out)
    • Available if both Losses and Temparature calculation are enabled. In this case T_junctions is an output since the case thermal model is inside the component and case temperatures are provided as an input to the component.
    • Represents the junction temperatures of the diode
    • T_junctions port is scalar - diode junction temperature

General (Tab)

  • Resistance
    • This property is ignored in TyphoonSim. Resistance value will not affect TyphoonSim simulation at all.
    • Available when diode is modeled as LC switch (Use ideal switch model option is unchecked).
    • Resistance is used to model the inductance of closed switch and capacitance of the open switch. More information about this property, can be found in the dedicated Diode models section.
  • Snubber type
    • This property is ignored in TyphoonSim. The chosen snubber type and its value will not affect TyphoonSim simulation at all.
    • Available when diode is modeled as ideal switch (Use ideal switch model option is checked).
    • Defines type of the snubber circuit. More information about this property, can be found in the dedicated Diode models section.
  • R
    • This property is ignored in TyphoonSim. The chosen snubber type and its value will not affect TyphoonSim simulation at all.
    • Available when diode is modeled as ideal switch (Use ideal switch model option is checked) and chosen Snubber type is not None.
    • Defines shunt resistance value of the snubber circuit. More information about this property, can be found in the dedicated Diode models section.
  • C
    • This property is ignored in TyphoonSim. The chosen snubber type and its value will not affect TyphoonSim simulation at all.
    • Available when diode is modeled as ideal switch (Use ideal switch model option is checked) and chosen Snubber type is R-C.
    • Defines shunt resistance value of the snubber circuit. More information about this property, can be found in the dedicated Diode models section.

Losses (Tab)

  • Losses calculation
    • Losses calculation is not supported in real-time/VHIL simulation yet.
    • Enables/disables losses calculation for diode component. More details can be found in the dedicated Losses calculation section.
  • Diode xml file
    • Available if Losses calculation is enabled
    • Used to load losses data for the diode from an xml file. More information about supported file formats can be found in the Losses calculation section.
  • Current values
    • Available if Losses calculation is enabled
    • Vector of current values that are used to specify diode losses at specific points. If losses data are loaded from an xml file, it will be filled automatically.
  • Voltage values
    • Available if Losses calculation is enabled
    • Vector of voltage values that are used to specify diode losses at specific points. If losses data are loaded from an xml file, it will be filled automatically.
  • Temp Values
    • Available if Losses calculation is enabled
    • Vector of temperature values that are used to specify diode losses at specific points. If losses data are loaded from an xml file, it will be filled automatically.
  • Vd table
    • Available if Losses calculation is enabled
    • 2D look up table for diode conduction voltage drop values. If losses data is loaded from xml file, it will be filled automatically. More information about table formats can be found in the Losses calculation section.
  • Ed off table
    • Available if Losses calculation is enabled
    • 3D look up table for diode turn off switching losses. If losses data is loaded from an xml file, it will be filled automatically. More information about table formats can be found in the Losses calculation section.
  • Temperatures calculation
    • Available if Losses calculation is enabled
    • Enables/disables losses temperature calculation for converter. Thermal model must be provided. More details can be found in the dedicated Temperatures calculation section.
  • Thermal networks type
    • Available if Temperature calculation is enabled
    • Specifies the type of thermal network model: Foster or Cauer
  • Diode Rth
    • Available if Temperature calculation is enabled
    • Diode thermal resistance
    • Vector
  • Diode Tth
    • Available if Temperature calculation is enabled and the Thermal network type is Foster
    • Diode thermal time constant
    • Vector
  • Diode Cth
    • Available if Temperature calculation is enabled and the Thermal network type is Cauer
    • Diode thermal time constant
    • Vector
  • Calculations execution rate
    • Available if Losses calculation or Forward voltage drop is enabled
    • Execution rate for losses calculation. Defines interval that will be used to update losses calculation inputs and outputs.

Advanced (Tab)

  • Use ideal switch model
    • This property is ignored in TyphoonSim. Resistance value will not affect TyphoonSim simulation at all. For simulation in TyphoonSim diode is modeled as changeable resistance (R_on/R_off).
    • Defines the type of diode implementation for real-time/VHIL simulation. More information about this property, can be found in the dedicated Diode models section.