Description
The back-to-back thyristor model consists of two similar thyristors connected in anti-parallel. This device helps in switching the current in either direction by applying a small current of either polarity between the gate and main terminal.
The model considers various factors like forward bias threshold, forward and reverse break over voltage, blocking current, snubber elements, holding current, on/off resistance. Depending on the user's requirement, there is also an option to select the precision functionality, which allows the user to compensate for errors due to digital implementation of the model during the state switching as a function of time step. The turnoff time Tq is the recovery time between the instant the anode current has decreased to 0 and the instant when the thyristor is capable of withstanding positive voltage without turning on again.
The model also has an option to be controlled from external signals and an option to enter the precision delay D.
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Mask and Parameters
General
| Name | Description | Unit | Variable = {Possible Values} |
|---|---|---|---|
| Vmin | Forward voltage drop | V | {[0,1e12]} |
| Ropen | Open state resistance | Ohm | {(0,1e12]} |
| Rclose | Closed state resistance | Ohm | {(0,1e12]} |
| Rsnubber | Snubber resistance | Ohm | {(0,1e12]} |
| Csnubber | Snubber capacitance | F | {[0,1e12]} |
| Control type | External Input pins: Schematic control signal; the received integer is converted to a binary string where each digit corresponds to a phase External Input sensors: Target digital inputs |
Advanced
| Name | Description | Unit | Variable = {Possible Values} | |
|---|---|---|---|---|
| Fail reset | Fail reset | {Enable, Disable} | ||
| Precision valve | Enable: Enables recalculation of the state switch command using exact time between steps (as percentage of time step) Disable: does not use precision valve | {Enable, Disable} | ||
| Imin | Holding current | A | {[0,1e12]} | |
| Tq | Thyristor turn off time | s | {[0,1e12]} | |
| Fbov | Forward break over voltage | V | {[0,1e12]} | |
| Rbov | Reverse break over voltage | V | {[0,1e12]} | |
Ports, Inputs, Outputs and Signals Available for Monitoring
Ports
| Name | Description |
|---|---|
| Net_1 | Network connection |
| Net_2 | Network connection |
Inputs
| Name | Description |
|---|---|
| D | Delay used for precision valves |
| P | Binary coded firing pulses |
Outputs
Sensors
| Name | Description | Unit |
|---|---|---|
| D | Delay used for precision valve, measured from changing point to current time step | s |
| P | Binary coded firing pulses | |
| FailSig | Fail reset signal | |
| I | Diode current | A |
| Isw | Switch current | A |
| Delay | Delay due to forward voltage drop | s |
| Delay12 | Delay in forward Thyristor mode | s |
| Delay21 | Delay in anti parallel Thyristor mode | s |
| DelayExt12 | Delay for external trigger | s |
| DelayExt21 | Delay for external trigger | s |
| Cmd12 | Forward Signal state command | |
| Cmd21 | Anti parallel Signal state command | |
| CmdExt12 | Signal state external command | |
| CmdExt21 | Signal state external command | |
| State12 | Forward Thyristor state | |
| State21 | Anti-parallel Thyristor state |
Note that in the previous table, the suffixes "12" and "21" denote the forward (positive to negative) and anti-parallel (negative to positive) thyristor states respectively. One can identify the positive terminal of the device as the one closest to the input pin. So, in the default (not flipped or rotated) thyristor back-to-back icon, the positive terminal is the top one.