Ideal Semiconductor Switch
The ideal solid-state controlled switch.
Description
The Ideal Semiconductor Switch unit is an ideal semiconductor controlled switch that uses an external signal and phase current values to break an electrical circuit.
The figure below shows a typical volt-ampere characteristic of an ideal semiconductor switch:
If the voltage across the gate-cathode circuit exceeds the threshold voltage set in the Threshold voltage, Vth parameter, the ideal semiconductor switch is in the on state. Otherwise, the switch is in the off state.
In the on state (passing current in the forward direction), the anode-cathode circuit of the switch behaves as a linear resistor with On-state resistance.
In the OFF state, the anode-cathode switch circuit behaves as a linear resistor with low Off-state conductance.
Using the parameters of the Integral Diode section, a protection diode (suppressor) can be switched on. The suppressor protects the semiconductor key by providing a conductive path for reverse current. An inductive load can create a large reverse voltage spike when the semiconductor switch suddenly cuts off the voltage supply to the load.
The table shows the recommended values for the Integral protection diode parameter depending on the intended purpose.
Purpose |
Value to select |
Block behaviour |
Simulation speed priority. |
|
The block includes an integral copy of the Diode block. Use the Integral Diode parameters to set the parameters of the internal Diode block. |
Precise setting of charge dynamics in reverse mode. |
|
The block includes an integral copy of the dynamic model of the Diode block. Use the Integral Diode parameters to set the parameters of the internal Diode unit. |
Ports
Input
G - gate contact (pin)
scalar
Control signal port associated with the switch gate.
Dependencies
To use this port, set the Gate-control port parameter to Signal control port.
Non-directional
G - gate contact
electricity
Electrical port associated with the switch gate contact.
Dependencies
To use this port, set the Gate-control port parameter to Electrical control port.
A is the anode contact
`electrical
Electrical port associated with the anode contact of the switch.
K is the cathode contact
electricity
Electrical port associated with the cathode contact of the switch.
Parameters
Main
Gate-control port - defines the control port: scalar or electric
Signal control port (by default) | Electrical control port
Scalar or electrical control port for the switch gate control.
On-state resistance - On-state resistance
0.001 Ohm (by default).
On-state resistance between anode and cathode.
Off-state conductance - off-state conductance
`1e-6 1/Ohm (by default)
Anode-to-cathode conductance in the off-state. The value must be less than , where is the value of resistance in the switched on state.
Threshold voltage, Vth - threshold voltage
`0.5 V (by default)
Threshold voltage for the gate-cathode circuit. The switch turns on when the gate-cathode circuit voltage exceeds this value.
Integral Diode
Integral protection diode - internal protection diode (suppressor)
None (by default) | Diode with no dynamics | Diode with charge dynamics
Specify whether the unit includes a protection diode (suppressor). By default, `None' is used.
If the internal protection diode is to be enabled, two options are available:
-
Diode with no dynamics. -
`Diode with charge dynamics'.
Forward voltage - forward voltage
0.8 V (by default)
The minimum voltage required by the + and - ports of the block to make the gradient of the diode’s volt-ampere characteristic equal to , where is the resistance value at the switch on.
Dependencies
To use this parameter, set the Integral protection diode parameter to Diode with no dynamics or Diode with charge dynamics.
On resistance - resistance when directly connected
0.001 ohms (by default).
The diode resistance in the open state when the voltage is higher than the value set by the Forward voltage parameter.
Dependencies
To use this parameter, set Integral protection diode to Protection diode with no dynamics or Protection diode with charge dynamics.
Off conductance - closed state conductance
1e-5 1/ohm (by default).
The conductance of the diode when switched back on.
Dependencies
To use this parameter, set Integral protection diode to Diode with no dynamics or Diode with charge dynamics.
Junction capacitance - junction capacitance
50e-9 F (By default).
The value of the capacitance inherent in the depletion zone transition, acting as a dielectric and separating the anode and cathode junctions.
Dependencies
To use this parameter, set Integral protection diode to `Diode with charge dynamics'.
Initial forward current when measuring, iRM - initial forward current when measuring iRM
300 A (By default) | positive scalar
Initial forward current (at the initial switch-on time) when measuring peak reverse current. This value must be greater than zero.
Dependencies
To use this parameter, set Integral protection diode to `Diode with charge dynamics'.
Rate of change of current when measuring, iRM - rate of change of current when measuring iRM
-50 A/µs (By default) | `negative scalar'.
Rate of change of current when measuring peak reverse current. This value must be less than zero.
Dependencies
To use this parameter, set Integral protection diode to `Diode with charge dynamics'.
Reverse recovery time parameterization - type of reverse recovery time definition
| Specify reverse recovery time directly (by default) | Specify stretch factor | Specify reverse recovery charge.
Specifies how to specify the reverse recovery time in a block. By default, Specify reverse recovery time directly is used.
Selecting Specify stretch factor or Specify reverse recovery charge specifies the value used by the block to calculate the reverse recovery time.
Dependencies
To use this option, set Integral protection diode to `Diode with charge dynamics'.
Reverse recovery time, trr - reverse recovery time
`15 µs (By default)
The amount of time it takes for a diode to switch off when its voltage reverses polarity from forward bias to reverse bias.
The interval between when the current initially crosses zero (when the diode switches off) and when the current drops to less than 10% of the peak current. The value of Reverse recovery time, trr must be greater than the value of Peak reverse current, iRM divided by the value of Rate of change of current when measuring, iRM.
Dependencies
To use this parameter, set the Integral protection diode parameter to `Diode with charge dynamics' and the Reverse recovery time parameterization parameter is set to `Specify reverse recovery time directly'.
Reverse recovery time stretch factor - reverse recovery time stretch factor
3 (By default).
The value that the block uses to calculate Reverse recovery time, trr. This value must be greater than 1. Specifying the stretch factor is a simpler way of parameterising the reverse recovery time than specifying the reverse recovery charge. The larger the value of the stretch factor, the longer the time required for the reverse recovery current to dissipate.
Dependencies
To use this parameter, set Integral protection diode to `Diode with charge dynamics' and Reverse recovery time parameterization is set to `Specify stretch factor'.
Reverse recovery charge, Qrr - reverse recovery charge
1500 µCl (by default).
The value the unit uses to calculate Reverse recovery time, trrr. Use this parameter if the unit parameters specify the reverse recovery charge value instead of the reverse recovery time value as the type of reverse recovery time definition.
The reverse recovery charge is the total charge that continues to dissipate after the diode is switched off. The value must be less than , where:
-
- the value specified for the Peak reverse current parameter, iRM.
-
- value specified for the parameter Rate of change of current when measuring iRM.
Dependencies
To use this parameter, set Integral protection diode to `Diode with charge dynamics' and Reverse recovery time parameterization to `Specify reverse recovery charge'.