Discrepancies between single switches

Here is summary of the different single switch types supported in eHS. It is important to emphasize that transient behavior is not considered in the modeling, thus the only discrepancy between them is their static characteristics.

Switches	Description

Switches

Description

Ideal switch

This switch allows current to flow in both directions and can also block the voltage in both directions; its behavior depends entirely on the gate signal.

ideal switch static characteristics

Breaker

This switch allows current to flow in both directions and can also block the voltage in both directions. It conducts when the gate is on, but it blocks when the gate is off and the current is equals to zero.

breaker static characteristics

Diode

This switch allows conduction in only one direction (current flowing from anode to cathode); when polarized with reverse voltage, the switch blocks.

It doesn’t receive any gate signal; its state only depends on the evolution of the electrical variables in the external circuit (spontaneous commutation).

diode static characteristics

Thyristor

This switch allows conduction in only one direction (current flowing from anode to cathode) when the gate is on and it is directly polarized. Once the switch is conducting, it is blocked by a reverse current.

Thyristor static characteristics

FET

This switch allows current to flow in both directions and can also block the voltage in both directions; its behavior depends on the gate signal.

FET static characteristics

IGBT

This switch allows current to flow in one direction and it is able to block direct voltage. It is always blocked when reverse polarized.

IGBT static characteristics

IGBT with Antiparallel Diode

FET with Antiparallel Diode

This switch allows current to flow in both direction, however it is able to block only direct voltage; it conducts when reverse polarized (through the anti-parallel diode).

IGBT and FET with Antiparallel Diode static characteristics

Note: in curves presented above, the slope of the line is defined by the internal resistances R_on and R_off.

Voltage-current ratio for a closed switch (left) and an open switch (right) is defined by the parameters R_on and R_off.