How to use the PSIM On-Off Controllers
Altair EmployeeOn the Library browser we find two switch controllers, the “normal” On-Of Controller, and the On-Off Controller (multi-level). The multi-level controller contains the “normal” controller and other multiple combinations of inputs and outputs and should be chosen according to the application.
The multilevel switch can handle both Power and Control input signals:
Control Input
These controllers work with a logic input signal (transition from 0 to 1 and vice versa in the period of a timestep) and when used with an analog signal at the input acts as if there’s a threshold with a value of 0.1.
This input value is referenced towards the ground of the control circuit. Keep in mind that the ground for the control circuit and the power circuit are treated as separate even if they use the same symbol.
Figure 1. An example of ramp switching on a control to ideal model
Power Input
These controllers determine the change of state with a voltage threshold defined in the attributes or by non-ideal switch models. Its input has two ports and can be referenced at any other potential (for instance, a voltage divider like in figure 2).
Figure 2. An example of a pulse on a voltage divider switching an ideal model.
Be mindful that power circuits and control circuits are solved separately (red and green connections respectively), and there is one time step delay between these two solutions. This might cause a one-step difference in the activation of an ideal switch with a voltage input. To find out more about this, please read Power/Control Circuit Representation and Interface part of the PSIM help.
If you want to know how to select a time step for your PSIM simulations, check out this video.
Now, there are 4 types of on-off controllers depending on the inputs and the switch model they are used for. these are the following:
Ideal Switch Controllers
To use an ideal model, it’s necessary to use a switch controller. These controllers are connected directly to the gate of the model, there’s no need for another connection to the source (or emitter) node.
Keep in mind that thermal models are ideal but can calculate losses with information from the component’s datasheet.
Control to Ideal Switch (Or the “Normal” On-Off switch controller from the library browser)
On this controller, the input is expected to be a control signal and is connected to an ideal model.
Power to Ideal Switch
On this controller, the input is expected to be a power signal on its two input ports and is connected to the ideal model. The threshold voltage for activation is defined within the controller’s parameters.
Non-Ideal Switch Controllers
We can use controllers for non-ideal models (Level 1, Level 2, Level 3, and SPICE), these are connected to the gate and source (or emitter) nodes of the model.
It’s not mandatory to use these controllers. To allow more flexibility, we can use these, or a more sophisticated gate drive circuit depending on how complex or high fidelity we want the simulation to be.
Control to Model
On this controller, the input is expected to be a control signal and a two-port output to the model.
The Gate voltage High, Gate Voltage low and Gate Resistance are defined within the parameters of the controller.
Power to Model
On this controller, the input is expected to be a power signal on its two input ports. The output is going to be the same as its input.
