Simulation of Switched Filter Circuit Using Nodal State-Space SSN Algorithm

The circuit shows the capability of ARTEMiS to accurately simulate a circuit using the State-Space Nodal (SSN) algorithm. The SSN algorithm is nodal admittance based method in which group equations are found first using a state-space method. SSN groups can be seen as a generalized branch in EMTP terminology. The state-space group first compute their Thevenin/Norton equivalent, derived from their state-space representation. Then, these Thevenin/Norton equivalents are solved simultaneously to solve the nodal voltages at their connection points using a nodal admittance method.

The switched filter model has two SSN groups defined by the Nodal Interface Block. One group is made of the switched inductive 3-phase source while the other is made of a large capacitor and RLC series filter.

The inductive source requires a V-type nodal interface (defined in the Nodal Interface Block, or NIB, menu). V-type means that the group will see the nodal point as a (temporarily undetermined) voltage source.

The filter requires an I-type nodal interface. I-type means that the group will see the nodal point as a (temporarily unknown) current source.

The reason for this interface type (I-type or V-type) is that the group state-space equation is computed inside the SSN algorithm and the unknown nodal point must respect the state-space link/branch restrictions.

Demonstration

Start the simulation and observe the simulation results. You can disable SSN by unchecking the option in the 'ARTEMiS GUIde' block and comparing against regular ARTEMiS solvers. You can also compare with SPS by deleting the 'ARTEMiS GUIDE'. The Nodal Interface Block (NIB) is transparent when SSN solver is disabled to facilitate the model design.