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Table of Contents

 

 

Description

The thermal losses feature allows the user to assign switching losses, and conducting losses for 2-levels bridge. Every 2-levels bridge can be configured using one of four lookup tables defined for the switches, and their anti-parallel diode. Note that this feature does not affect the simulation results. Losses shown here are not added nor subtracted from the simulation.

Mask parameters

enable: By checking this option, the thermal loss feature will be enabled.

Conducting losses

VCE lookup table [V]: This parameter indicates the forward voltage when the component conducts. It is given by a 2-dimensional lookup table. It is function of the device current and temperature. Temperature has a maximum of 4 break points and current a maximum of 16 break points. Therefore the lookup table has a maximum size of 4 lines, by 16 columns. size(switchLosses.conductingVce) = [4, 16]

VCE lookup table when diode/switch conducting [V] : This parameter is only used in the case of a MOSFET, where the switch can conduct a reverse current. In this particular case, conducting losses will be dissipated in both the switch and the diode, if the switch is conducting when the current is in reverse. The table is given by a 2-dimensional lookup table. It is function of the device current and temperature. Temperature has a maximum of 4 break points and current a maximum of 16 break points. Therefore the lookup table has a maximum size of 4 lines, by 16 columns. (size(switchLosses.reverseConductingVce) = [4, 16])

Switch/Diode current axis breakpoints [Amps]: This parameter indicate the different break points for the current axis of the VCE lookup table. A minimum of 2 break points are required and a maximum of 16 break points are supported.

Temperature axis breakpoints [Degrees Celsius]: This parameter indicate the different break point for the temperature axis of the VCE lookup table. A minimum of 1 break point is required and a maximum of 4 break points are supported.

Switching losses

TurnOn lookup table [J]: This parameter indicates the number of joule dissipated during turn ON. It is given by a 3-dimensional lookup table. It is function of the device current, voltage, and temperature. Temperature and Voltage have a maximum of 4 break points, and current a maximum of 16 break points. Therefore the lookup table has a maximum size of 4 lines for the voltages, by 16 columns for the currents, by 4 depth for the temperature. (size(switchLosses.turnOnTable) = [4, 16, 4])

TurnOff lookup table [J]: This parameter indicates the number of joule dissipated during turn OFF. It is given by a 3-dimensional lookup table. It is function of the device current, voltage, and temperature. Temperature and Voltage have a maximum of 4 break points, and current a maximum of 16 break points. Therefore the lookup table has a maximum size of 4 lines for the voltages, by 16 columns for the currents, by 4 depth for the temperature. (size(switchLosses.turnOffTable) = [4, 16, 4])

Switch/Diode current axis breakpoints [Amps]: This parameter indicates the different break points for the current axis of the Turn ON/OFF lookup table. A minimum of 2 break points are required and a maximum of 16 break points are supported.

DC Voltage axis breakpoints [Volts]: This parameter indicates the different break points for the voltage axis of the Turn ON/OFF lookup table. A minimum of 1 break point is required and a maximum of 4 break points are supported.

Temperature axis breakpoints [Degrees Celsius]: This parameter indicates the different break points for the temperature axis of the Turn ON/OFF lookup table. A minimum of 1 break point is required and a maximum of 4 break points are supported.

Configuration Panel

Configuration: This button enables the user to open the eHS Thermal losses Configuration panel.

This table shows every Inverter leg detected in the circuit. The eHS will automatically populate the list of legs from the Universal bridge blocks found in the circuit model.

• The first column shows their names.

• The Enable column allows to choose which inverters leg are monitored. A maximum of 30 two-level inverters leg, or 120 devices, can be monitored during a simulation.

• The DC Voltage and AC Current columns define the measurement indices used to compute the thermal losses.

• The thermal model column lets the user assign one of the four lookup table.

• T° port indices column indicates where the component temperature should send on the devices T° port vector.

• Upper and lower switch gate index define the inverter gate indices used to compute the thermal losses.

The information of which gate and measurement indices to use is based on the Schematic Editor model and eHS Build Report. Define which measurements and gates you want to simulate thermal losses on in your schema and find their corresponding indices in the build report.

For more information on how to fill the different Thermal model and their Switch and Diode characteristics please use the following link for the Thermal loss documentation.